diff --git a/src/BroList.h b/src/BroList.h
index 57b1fba2af..fa30fa663f 100644
--- a/src/BroList.h
+++ b/src/BroList.h
@@ -7,8 +7,8 @@
 FORWARD_DECLARE_NAMESPACED(Expr, zeek::detail);
 typedef PList<zeek::detail::Expr> expr_list;
 
-class ID;
-typedef PList<ID> id_list;
+FORWARD_DECLARE_NAMESPACED(ID, zeek::detail);
+typedef PList<zeek::detail::ID> id_list;
 
 class Val;
 typedef PList<Val> val_list;
diff --git a/src/DebugCmds.cc b/src/DebugCmds.cc
index 93e1ef9f0e..3cc5baa7f8 100644
--- a/src/DebugCmds.cc
+++ b/src/DebugCmds.cc
@@ -30,13 +30,13 @@ using namespace std;
 //
 // Helper routines
 //
-bool string_is_regex(const string& s)
+static bool string_is_regex(const string& s)
 	{
 	return strpbrk(s.data(), "?*\\+");
 	}
 
-void lookup_global_symbols_regex(const string& orig_regex, vector<ID*>& matches,
-					bool func_only = false)
+static void lookup_global_symbols_regex(const string& orig_regex, vector<zeek::detail::ID*>& matches,
+                                        bool func_only = false)
 	{
 	if ( streq(orig_regex.c_str(), "") )
 		return;
@@ -61,18 +61,18 @@ void lookup_global_symbols_regex(const string& orig_regex, vector<ID*>& matches,
 	Scope* global = global_scope();
 	const auto& syms = global->Vars();
 
-	ID* nextid;
+	zeek::detail::ID* nextid;
 	for ( const auto& sym : syms )
 		{
-		ID* nextid = sym.second.get();
+		zeek::detail::ID* nextid = sym.second.get();
 		if ( ! func_only || nextid->GetType()->Tag() == TYPE_FUNC )
 			if ( ! regexec (&re, nextid->Name(), 0, 0, 0) )
 				matches.push_back(nextid);
 		}
 	}
 
-void choose_global_symbols_regex(const string& regex, vector<ID*>& choices,
-					bool func_only = false)
+static void choose_global_symbols_regex(const string& regex, vector<zeek::detail::ID*>& choices,
+                                        bool func_only = false)
 	{
 	lookup_global_symbols_regex(regex, choices, func_only);
 
@@ -111,7 +111,7 @@ void choose_global_symbols_regex(const string& regex, vector<ID*>& choices,
 		int option = atoi(input.c_str());
 		if ( option > 0 && option <= (int) choices.size() )
 			{
-			ID* choice = choices[option - 1];
+			zeek::detail::ID* choice = choices[option - 1];
 			choices.clear();
 			choices.push_back(choice);
 			return;
@@ -398,7 +398,7 @@ int dbg_cmd_break(DebugCmd cmd, const vector<string>& args)
 		vector<string> locstrings;
 		if ( string_is_regex(args[0]) )
 			{
-			vector<ID*> choices;
+			vector<zeek::detail::ID*> choices;
 			choose_global_symbols_regex(args[0], choices, true);
 			for ( unsigned int i = 0; i < choices.size(); ++i )
 				locstrings.push_back(choices[i]->Name());
diff --git a/src/Frame.cc b/src/Frame.cc
index 7c1470d2dc..628bfc5715 100644
--- a/src/Frame.cc
+++ b/src/Frame.cc
@@ -77,7 +77,7 @@ void Frame::SetElementWeak(int n, Val* v)
 	frame[n] = {{AdoptRef{}, v}, true};
 	}
 
-void Frame::SetElement(const ID* id, IntrusivePtr<Val> v)
+void Frame::SetElement(const zeek::detail::ID* id, IntrusivePtr<Val> v)
 	{
 	if ( closure )
 		{
@@ -106,7 +106,7 @@ void Frame::SetElement(const ID* id, IntrusivePtr<Val> v)
 	SetElement(id->Offset(), std::move(v));
 	}
 
-const IntrusivePtr<Val>& Frame::GetElementByID(const ID* id) const
+const IntrusivePtr<Val>& Frame::GetElementByID(const zeek::detail::ID* id) const
 	{
 	if ( closure )
 		{
@@ -478,7 +478,7 @@ void Frame::AddKnownOffsets(const id_list& ids)
 		offset_map = std::make_unique<OffsetMap>();
 
 	std::transform(ids.begin(), ids.end(), std::inserter(*offset_map, offset_map->end()),
-		       [] (const ID* id) -> std::pair<std::string, int>
+		       [] (const zeek::detail::ID* id) -> std::pair<std::string, int>
 		       {
 		       return std::make_pair(std::string(id->Name()), id->Offset());
 		       });
@@ -523,10 +523,10 @@ void Frame::ClearElement(int n)
 		frame[n] = {nullptr, false};
 	}
 
-bool Frame::IsOuterID(const ID* in) const
+bool Frame::IsOuterID(const zeek::detail::ID* in) const
 	{
 	return std::any_of(outer_ids.begin(), outer_ids.end(),
-		[&in](ID* id)-> bool { return strcmp(id->Name(), in->Name()) == 0; });
+		[&in](zeek::detail::ID* id)-> bool { return strcmp(id->Name(), in->Name()) == 0; });
 	}
 
 broker::expected<broker::data> Frame::SerializeIDList(const id_list& in)
@@ -588,7 +588,7 @@ Frame::UnserializeIDList(const broker::vector& data)
 			return std::make_pair(false, std::move(rval));
 			}
 
-		ID* id = new ID(has_name->c_str(), SCOPE_FUNCTION, false);
+		auto* id = new zeek::detail::ID(has_name->c_str(), zeek::detail::SCOPE_FUNCTION, false);
 		id->SetOffset(*has_offset);
 		rval.push_back(id);
 		std::advance(where, 1);
diff --git a/src/Frame.h b/src/Frame.h
index d7a1a26a28..65dff91eb8 100644
--- a/src/Frame.h
+++ b/src/Frame.h
@@ -66,8 +66,8 @@ public:
 	 * @param id the ID to associate
 	 * @param v the value to associate it with
 	 */
-	void SetElement(const ID* id, IntrusivePtr<Val> v);
-	void SetElement(const IntrusivePtr<ID>& id, IntrusivePtr<Val> v)
+	void SetElement(const zeek::detail::ID* id, IntrusivePtr<Val> v);
+	void SetElement(const IntrusivePtr<zeek::detail::ID>& id, IntrusivePtr<Val> v)
 		{ SetElement(id.get(), std::move(v)); }
 
 	/**
@@ -77,11 +77,11 @@ public:
 	 * @param id the id who's value to retreive
 	 * @return the value associated with *id*
 	 */
-	const IntrusivePtr<Val>& GetElementByID(const IntrusivePtr<ID>& id) const
+	const IntrusivePtr<Val>& GetElementByID(const IntrusivePtr<zeek::detail::ID>& id) const
 		{ return GetElementByID(id.get()); }
 
 	[[deprecated("Remove in v4.1.  Use GetElementByID().")]]
-	Val* GetElement(const ID* id) const
+	Val* GetElement(const zeek::detail::ID* id) const
 		{ return GetElementByID(id).get(); }
 
 	/**
@@ -247,7 +247,7 @@ private:
 		bool weak_ref;
 	};
 
-	const IntrusivePtr<Val>& GetElementByID(const ID* id) const;
+	const IntrusivePtr<Val>& GetElementByID(const zeek::detail::ID* id) const;
 
 	/**
 	 * Sets the element at index *n* of the underlying array to *v*, but does
@@ -273,7 +273,7 @@ private:
 	void ClearElement(int n);
 
 	/** Have we captured this id? */
-	bool IsOuterID(const ID* in) const;
+	bool IsOuterID(const zeek::detail::ID* in) const;
 
 	/** Serializes an offset_map */
 	static broker::expected<broker::data>
diff --git a/src/Func.cc b/src/Func.cc
index ad1c7b03b9..c2a498ceb5 100644
--- a/src/Func.cc
+++ b/src/Func.cc
@@ -122,7 +122,7 @@ Func::Func(Kind arg_kind) : kind(arg_kind)
 Func::~Func() = default;
 
 void Func::AddBody(IntrusivePtr<zeek::detail::Stmt> /* new_body */,
-                   const std::vector<IntrusivePtr<ID>>& /* new_inits */,
+                   const std::vector<IntrusivePtr<zeek::detail::ID>>& /* new_inits */,
                    size_t /* new_frame_size */, int /* priority */)
 	{
 	Internal("Func::AddBody called");
@@ -268,8 +268,8 @@ void Func::CheckPluginResult(bool handled, const IntrusivePtr<Val>& hook_result,
 	}
 	}
 
-BroFunc::BroFunc(const IntrusivePtr<ID>& arg_id, IntrusivePtr<zeek::detail::Stmt> arg_body,
-                 const std::vector<IntrusivePtr<ID>>& aggr_inits,
+BroFunc::BroFunc(const IntrusivePtr<zeek::detail::ID>& arg_id, IntrusivePtr<zeek::detail::Stmt> arg_body,
+                 const std::vector<IntrusivePtr<zeek::detail::ID>>& aggr_inits,
                  size_t arg_frame_size, int priority)
 	: Func(BRO_FUNC)
 	{
@@ -450,7 +450,7 @@ IntrusivePtr<Val> BroFunc::Invoke(zeek::Args* args, Frame* parent) const
 	}
 
 void BroFunc::AddBody(IntrusivePtr<zeek::detail::Stmt> new_body,
-                      const std::vector<IntrusivePtr<ID>>& new_inits,
+                      const std::vector<IntrusivePtr<zeek::detail::ID>>& new_inits,
                       size_t new_frame_size, int priority)
 	{
 	if ( new_frame_size > frame_size )
@@ -575,7 +575,7 @@ void BroFunc::Describe(ODesc* d) const
 	}
 
 IntrusivePtr<zeek::detail::Stmt> BroFunc::AddInits(IntrusivePtr<zeek::detail::Stmt> body,
-                                                   const std::vector<IntrusivePtr<ID>>& inits)
+                                                   const std::vector<IntrusivePtr<zeek::detail::ID>>& inits)
 	{
 	if ( inits.empty() )
 		return body;
diff --git a/src/Func.h b/src/Func.h
index 6dbe12edac..b1b653ddc4 100644
--- a/src/Func.h
+++ b/src/Func.h
@@ -22,11 +22,11 @@
 class Val;
 class FuncType;
 class Frame;
-class ID;
 class Scope;
 
 FORWARD_DECLARE_NAMESPACED(Stmt, zeek::detail);
 FORWARD_DECLARE_NAMESPACED(CallExpr, zeek::detail);
+FORWARD_DECLARE_NAMESPACED(ID, zeek::detail);
 
 class Func : public BroObj {
 public:
@@ -79,7 +79,7 @@ public:
 
 	// Add a new event handler to an existing function (event).
 	virtual void AddBody(IntrusivePtr<zeek::detail::Stmt> new_body,
-	                     const std::vector<IntrusivePtr<ID>>& new_inits,
+	                     const std::vector<IntrusivePtr<zeek::detail::ID>>& new_inits,
 	                     size_t new_frame_size, int priority = 0);
 
 	virtual void SetScope(IntrusivePtr<Scope> newscope);
@@ -129,8 +129,8 @@ protected:
 
 class BroFunc final : public Func {
 public:
-	BroFunc(const IntrusivePtr<ID>& id, IntrusivePtr<zeek::detail::Stmt> body,
-	        const std::vector<IntrusivePtr<ID>>& inits,
+	BroFunc(const IntrusivePtr<zeek::detail::ID>& id, IntrusivePtr<zeek::detail::Stmt> body,
+	        const std::vector<IntrusivePtr<zeek::detail::ID>>& inits,
 	        size_t frame_size, int priority);
 
 	~BroFunc() override;
@@ -168,7 +168,7 @@ public:
 	broker::expected<broker::data> SerializeClosure() const;
 
 	void AddBody(IntrusivePtr<zeek::detail::Stmt> new_body,
-	             const std::vector<IntrusivePtr<ID>>& new_inits,
+	             const std::vector<IntrusivePtr<zeek::detail::ID>>& new_inits,
 	             size_t new_frame_size, int priority) override;
 
 	/** Sets this function's outer_id list. */
@@ -179,8 +179,9 @@ public:
 
 protected:
 	BroFunc() : Func(BRO_FUNC)	{}
-	IntrusivePtr<zeek::detail::Stmt> AddInits(IntrusivePtr<zeek::detail::Stmt> body,
-	                                          const std::vector<IntrusivePtr<ID>>& inits);
+	IntrusivePtr<zeek::detail::Stmt> AddInits(
+		IntrusivePtr<zeek::detail::Stmt> body,
+		const std::vector<IntrusivePtr<zeek::detail::ID>>& inits);
 
 	/**
 	 * Clones this function along with its closures.
@@ -269,9 +270,9 @@ struct function_ingredients {
 	// to build a function.
 	function_ingredients(IntrusivePtr<Scope> scope, IntrusivePtr<zeek::detail::Stmt> body);
 
-	IntrusivePtr<ID> id;
+	IntrusivePtr<zeek::detail::ID> id;
 	IntrusivePtr<zeek::detail::Stmt> body;
-	std::vector<IntrusivePtr<ID>> inits;
+	std::vector<IntrusivePtr<zeek::detail::ID>> inits;
 	int frame_size;
 	int priority;
 	IntrusivePtr<Scope> scope;
diff --git a/src/ID.cc b/src/ID.cc
index b21200155d..73bd2b50cb 100644
--- a/src/ID.cc
+++ b/src/ID.cc
@@ -31,7 +31,7 @@ IntrusivePtr<TableType> zeek::id::count_set;
 IntrusivePtr<VectorType> zeek::id::string_vec;
 IntrusivePtr<VectorType> zeek::id::index_vec;
 
-const IntrusivePtr<ID>& zeek::id::find(std::string_view name)
+const IntrusivePtr<zeek::detail::ID>& zeek::id::find(std::string_view name)
 	{
 	return global_scope()->Find(name);
 	}
@@ -102,6 +102,8 @@ void zeek::id::detail::init()
 	index_vec = zeek::id::find_type<VectorType>("index_vec");
 	}
 
+namespace zeek::detail {
+
 ID::ID(const char* arg_name, IDScope arg_scope, bool arg_is_export)
 	{
 	name = copy_string(arg_name);
@@ -118,6 +120,9 @@ ID::ID(const char* arg_name, IDScope arg_scope, bool arg_is_export)
 	SetLocationInfo(&start_location, &end_location);
 	}
 
+ID::ID(const char* arg_name, ::IDScope arg_scope, bool arg_is_export) :
+	ID(arg_name, static_cast<IDScope>(arg_scope), arg_is_export) {}
+
 ID::~ID()
 	{
 	delete [] name;
@@ -205,7 +210,7 @@ void ID::SetVal(IntrusivePtr<Val> v, init_class c)
 		}
 	}
 
-void ID::SetVal(IntrusivePtr<zeek::detail::Expr> ev, init_class c)
+void ID::SetVal(IntrusivePtr<Expr> ev, init_class c)
 	{
 	const auto& a = attrs->Find(c == INIT_EXTRA ? ATTR_ADD_FUNC : ATTR_DEL_FUNC);
 
@@ -215,6 +220,16 @@ void ID::SetVal(IntrusivePtr<zeek::detail::Expr> ev, init_class c)
 	EvalFunc(a->GetExpr(), std::move(ev));
 	}
 
+void ID::SetVal(IntrusivePtr<Val> v, ::init_class c)
+	{
+	SetVal(v, static_cast<init_class>(c));
+	}
+
+void ID::SetVal(IntrusivePtr<Expr> ev, ::init_class c)
+	{
+	SetVal(ev, static_cast<init_class>(c));
+	}
+
 bool ID::IsRedefinable() const
 	{
 	return GetAttr(ATTR_REDEF) != nullptr;
@@ -276,7 +291,7 @@ bool ID::IsDeprecated() const
 	return GetAttr(ATTR_DEPRECATED) != nullptr;
 	}
 
-void ID::MakeDeprecated(IntrusivePtr<zeek::detail::Expr> deprecation)
+void ID::MakeDeprecated(IntrusivePtr<Expr> deprecation)
 	{
 	if ( IsDeprecated() )
 		return;
@@ -337,13 +352,13 @@ void ID::SetOption()
 		}
 	}
 
-void ID::EvalFunc(IntrusivePtr<zeek::detail::Expr> ef, IntrusivePtr<zeek::detail::Expr> ev)
+void ID::EvalFunc(IntrusivePtr<Expr> ef, IntrusivePtr<Expr> ev)
 	{
 	auto arg1 = make_intrusive<zeek::detail::ConstExpr>(val);
 	auto args = make_intrusive<zeek::detail::ListExpr>();
 	args->Append(std::move(arg1));
 	args->Append(std::move(ev));
-	auto ce = make_intrusive<zeek::detail::CallExpr>(std::move(ef), std::move(args));
+	auto ce = make_intrusive<CallExpr>(std::move(ef), std::move(args));
 	SetVal(ce->Eval(nullptr));
 	}
 
@@ -655,3 +670,5 @@ std::vector<Func*> ID::GetOptionHandlers() const
 		v.push_back(element.second.get());
 	return v;
 	}
+
+}
diff --git a/src/ID.h b/src/ID.h
index ad11c5bf9b..5da63d9a29 100644
--- a/src/ID.h
+++ b/src/ID.h
@@ -22,16 +22,25 @@ class VectorType;
 class EnumType;
 class Attributes;
 
-FORWARD_DECLARE_NAMESPACED(Expr, zeek::detail);
+enum [[deprecated("Remove in v4.1. Use zeek::detail::init_class instead.")]] init_class { INIT_NONE, INIT_FULL, INIT_EXTRA, INIT_REMOVE, };
+enum [[deprecated("Remove in v4.1. Use zeek::detail::IDScope instead.")]] IDScope { SCOPE_FUNCTION, SCOPE_MODULE, SCOPE_GLOBAL };
 
-typedef enum { INIT_NONE, INIT_FULL, INIT_EXTRA, INIT_REMOVE, } init_class;
-typedef enum { SCOPE_FUNCTION, SCOPE_MODULE, SCOPE_GLOBAL } IDScope;
+namespace zeek::detail {
+
+class Expr;
+
+enum init_class { INIT_NONE, INIT_FULL, INIT_EXTRA, INIT_REMOVE, };
+enum IDScope { SCOPE_FUNCTION, SCOPE_MODULE, SCOPE_GLOBAL };
 
 class ID final : public BroObj, public notifier::Modifiable {
 public:
 	static inline const IntrusivePtr<ID> nil;
 
 	ID(const char* name, IDScope arg_scope, bool arg_is_export);
+
+	[[deprecated("Remove in v4.1. Use version that takes zeek::detail::IDScope")]]
+	ID(const char* name, ::IDScope arg_scope, bool arg_is_export);
+
 	~ID() override;
 
 	const char* Name() const	{ return name; }
@@ -71,7 +80,12 @@ public:
 	void SetVal(IntrusivePtr<Val> v);
 
 	void SetVal(IntrusivePtr<Val> v, init_class c);
-	void SetVal(IntrusivePtr<zeek::detail::Expr> ev, init_class c);
+	void SetVal(IntrusivePtr<Expr> ev, init_class c);
+
+	[[deprecated("Remove in v4.1. Use version that takes zeek::detail::init_class")]]
+	void SetVal(IntrusivePtr<Val> v, ::init_class c);
+	[[deprecated("Remove in v4.1. Use version that takes zeek::detail::init_class")]]
+	void SetVal(IntrusivePtr<Expr> ev, ::init_class c);
 
 	bool HasVal() const		{ return val != nullptr; }
 
@@ -118,7 +132,7 @@ public:
 
 	bool IsDeprecated() const;
 
-	void MakeDeprecated(IntrusivePtr<zeek::detail::Expr> deprecation);
+	void MakeDeprecated(IntrusivePtr<Expr> deprecation);
 
 	std::string GetDeprecationWarning() const;
 
@@ -145,7 +159,7 @@ public:
 	std::vector<Func*> GetOptionHandlers() const;
 
 protected:
-	void EvalFunc(IntrusivePtr<zeek::detail::Expr> ef, IntrusivePtr<zeek::detail::Expr> ev);
+	void EvalFunc(IntrusivePtr<Expr> ef, IntrusivePtr<Expr> ev);
 
 #ifdef DEBUG
 	void UpdateValID();
@@ -165,6 +179,10 @@ protected:
 
 };
 
+}
+
+using ID [[deprecated("Remove in v4.1. Use zeek::detail::ID instead.")]] = zeek::detail::ID;
+
 namespace zeek::id {
 
 /**
@@ -173,7 +191,7 @@ namespace zeek::id {
  * @return  The identifier, which may reference a nil object if no such
  * name exists.
  */
-const IntrusivePtr<ID>& find(std::string_view name);
+const IntrusivePtr<zeek::detail::ID>& find(std::string_view name);
 
 /**
  * Lookup an ID by its name and return its type.  A fatal occurs if the ID
diff --git a/src/RuleCondition.h b/src/RuleCondition.h
index d8f0b684b2..33fa4d6ccc 100644
--- a/src/RuleCondition.h
+++ b/src/RuleCondition.h
@@ -2,11 +2,13 @@
 
 #include <stdint.h> // for u_char
 #include <sys/types.h> // for u_char
+#include "util.h"
 
-class ID;
 class Rule;
 class RuleEndpointState;
 
+FORWARD_DECLARE_NAMESPACED(ID, zeek::detail);
+
 // Base class for all rule conditions except patterns and "header".
 class RuleCondition {
 public:
@@ -111,7 +113,5 @@ public:
 
 	void PrintDebug() override;
 private:
-	ID* id;
+	zeek::detail::ID* id;
 };
-
-
diff --git a/src/Scope.cc b/src/Scope.cc
index 657a27170e..008c43ff54 100644
--- a/src/Scope.cc
+++ b/src/Scope.cc
@@ -15,7 +15,7 @@ typedef PList<Scope> scope_list;
 static scope_list scopes;
 static Scope* top_scope;
 
-Scope::Scope(IntrusivePtr<ID> id,
+Scope::Scope(IntrusivePtr<zeek::detail::ID> id,
              std::unique_ptr<std::vector<IntrusivePtr<Attr>>> al)
 	: scope_id(std::move(id)), attrs(std::move(al))
 	{
@@ -35,17 +35,17 @@ Scope::Scope(IntrusivePtr<ID> id,
 		}
 	}
 
-const IntrusivePtr<ID>& Scope::Find(std::string_view name) const
+const IntrusivePtr<zeek::detail::ID>& Scope::Find(std::string_view name) const
 	{
 	auto entry = local.find(name);
 
 	if ( entry != local.end() )
 		return entry->second;
 
-	return ID::nil;
+	return zeek::detail::ID::nil;
 	}
 
-IntrusivePtr<ID> Scope::Remove(std::string_view name)
+IntrusivePtr<zeek::detail::ID> Scope::Remove(std::string_view name)
 	{
 	auto entry = local.find(name);
 
@@ -59,12 +59,12 @@ IntrusivePtr<ID> Scope::Remove(std::string_view name)
 	return nullptr;
 	}
 
-IntrusivePtr<ID> Scope::GenerateTemporary(const char* name)
+IntrusivePtr<zeek::detail::ID> Scope::GenerateTemporary(const char* name)
 	{
-	return make_intrusive<ID>(name, SCOPE_FUNCTION, false);
+	return make_intrusive<zeek::detail::ID>(name, zeek::detail::SCOPE_FUNCTION, false);
 	}
 
-std::vector<IntrusivePtr<ID>> Scope::GetInits()
+std::vector<IntrusivePtr<zeek::detail::ID>> Scope::GetInits()
 	{
 	auto rval = std::move(inits);
 	inits = {};
@@ -100,7 +100,7 @@ void Scope::Describe(ODesc* d) const
 
 	for ( const auto& entry : local )
 		{
-		ID* id = entry.second.get();
+		zeek::detail::ID* id = entry.second.get();
 		id->Describe(d);
 		d->NL();
 		}
@@ -110,7 +110,7 @@ TraversalCode Scope::Traverse(TraversalCallback* cb) const
 	{
 	for ( const auto& entry : local )
 		{
-		ID* id = entry.second.get();
+		zeek::detail::ID* id = entry.second.get();
 		TraversalCode tc = id->Traverse(cb);
 		HANDLE_TC_STMT_PRE(tc);
 		}
@@ -119,9 +119,9 @@ TraversalCode Scope::Traverse(TraversalCallback* cb) const
 	}
 
 
-const IntrusivePtr<ID>& lookup_ID(const char* name, const char* curr_module,
-                                  bool no_global, bool same_module_only,
-                                  bool check_export)
+const IntrusivePtr<zeek::detail::ID>& lookup_ID(const char* name, const char* curr_module,
+                                                bool no_global, bool same_module_only,
+                                                bool check_export)
 	{
 	std::string fullname = make_full_var_name(curr_module, name);
 
@@ -150,30 +150,30 @@ const IntrusivePtr<ID>& lookup_ID(const char* name, const char* curr_module,
 		return global_scope()->Find(globalname);
 		}
 
-	return ID::nil;
+	return zeek::detail::ID::nil;
 	}
 
-IntrusivePtr<ID> install_ID(const char* name, const char* module_name,
+IntrusivePtr<zeek::detail::ID> install_ID(const char* name, const char* module_name,
                             bool is_global, bool is_export)
 	{
 	if ( scopes.empty() && ! is_global )
 		reporter->InternalError("local identifier in global scope");
 
-	IDScope scope;
+	zeek::detail::IDScope scope;
 	if ( is_export || ! module_name ||
 	     (is_global &&
 	      normalized_module_name(module_name) == GLOBAL_MODULE_NAME) )
-		scope = SCOPE_GLOBAL;
+		scope = zeek::detail::SCOPE_GLOBAL;
 	else if ( is_global )
-		scope = SCOPE_MODULE;
+		scope = zeek::detail::SCOPE_MODULE;
 	else
-		scope = SCOPE_FUNCTION;
+		scope = zeek::detail::SCOPE_FUNCTION;
 
 	std::string full_name = make_full_var_name(module_name, name);
 
-	auto id = make_intrusive<ID>(full_name.data(), scope, is_export);
+	auto id = make_intrusive<zeek::detail::ID>(full_name.data(), scope, is_export);
 
-	if ( SCOPE_FUNCTION != scope )
+	if ( zeek::detail::SCOPE_FUNCTION != scope )
 		global_scope()->Insert(std::move(full_name), id);
 	else
 		{
@@ -189,7 +189,7 @@ void push_existing_scope(Scope* scope)
 	scopes.push_back(scope);
 	}
 
-void push_scope(IntrusivePtr<ID> id,
+void push_scope(IntrusivePtr<zeek::detail::ID> id,
                 std::unique_ptr<std::vector<IntrusivePtr<Attr>>> attrs)
 	{
 	top_scope = new Scope(std::move(id), std::move(attrs));
diff --git a/src/Scope.h b/src/Scope.h
index 146c5c051e..9ae4d5d976 100644
--- a/src/Scope.h
+++ b/src/Scope.h
@@ -13,31 +13,32 @@
 #include "TraverseTypes.h"
 
 template <class T> class IntrusivePtr;
-class ID;
 class BroType;
 class ListVal;
 
+FORWARD_DECLARE_NAMESPACED(ID, zeek::detail);
+
 class Scope : public BroObj {
 public:
-	explicit Scope(IntrusivePtr<ID> id,
+	explicit Scope(IntrusivePtr<zeek::detail::ID> id,
 	               std::unique_ptr<std::vector<IntrusivePtr<Attr>>> al);
 
-	const IntrusivePtr<ID>& Find(std::string_view name) const;
+	const IntrusivePtr<zeek::detail::ID>& Find(std::string_view name) const;
 
 	template<typename N>
 	[[deprecated("Remove in v4.1.  Use Find().")]]
-	ID* Lookup(N&& name) const
+	zeek::detail::ID* Lookup(N&& name) const
 		{ return Find(name).get(); }
 
 	template<typename N, typename I>
 	void Insert(N&& name, I&& id) { local[std::forward<N>(name)] = std::forward<I>(id); }
 
-	IntrusivePtr<ID> Remove(std::string_view name);
+	IntrusivePtr<zeek::detail::ID> Remove(std::string_view name);
 
 	[[deprecated("Remove in v4.1.  Use GetID().")]]
-	ID* ScopeID() const		{ return scope_id.get(); }
+	zeek::detail::ID* ScopeID() const		{ return scope_id.get(); }
 
-	const IntrusivePtr<ID>& GetID() const
+	const IntrusivePtr<zeek::detail::ID>& GetID() const
 		{ return scope_id; }
 
 	const std::unique_ptr<std::vector<IntrusivePtr<Attr>>>& Attrs() const
@@ -52,14 +53,14 @@ public:
 	size_t Length() const		{ return local.size(); }
 	const auto& Vars()	{ return local; }
 
-	IntrusivePtr<ID> GenerateTemporary(const char* name);
+	IntrusivePtr<zeek::detail::ID> GenerateTemporary(const char* name);
 
 	// Returns the list of variables needing initialization, and
 	// removes it from this Scope.
-	std::vector<IntrusivePtr<ID>> GetInits();
+	std::vector<IntrusivePtr<zeek::detail::ID>> GetInits();
 
 	// Adds a variable to the list.
-	void AddInit(IntrusivePtr<ID> id)
+	void AddInit(IntrusivePtr<zeek::detail::ID> id)
 		{ inits.emplace_back(std::move(id)); }
 
 	void Describe(ODesc* d) const override;
@@ -67,26 +68,26 @@ public:
 	TraversalCode Traverse(TraversalCallback* cb) const;
 
 protected:
-	IntrusivePtr<ID> scope_id;
+	IntrusivePtr<zeek::detail::ID> scope_id;
 	std::unique_ptr<std::vector<IntrusivePtr<Attr>>> attrs;
 	IntrusivePtr<BroType> return_type;
-	std::map<std::string, IntrusivePtr<ID>, std::less<>> local;
-	std::vector<IntrusivePtr<ID>> inits;
+	std::map<std::string, IntrusivePtr<zeek::detail::ID>, std::less<>> local;
+	std::vector<IntrusivePtr<zeek::detail::ID>> inits;
 };
 
 
 extern bool in_debug;
 
 // If no_global is true, don't search in the default "global" namespace.
-extern const IntrusivePtr<ID>& lookup_ID(const char* name, const char* module,
-                                         bool no_global = false,
-                                         bool same_module_only = false,
-                                         bool check_export = true);
+extern const IntrusivePtr<zeek::detail::ID>& lookup_ID(const char* name, const char* module,
+                                                       bool no_global = false,
+                                                       bool same_module_only = false,
+                                                       bool check_export = true);
 
-extern IntrusivePtr<ID> install_ID(const char* name, const char* module_name,
-                                   bool is_global, bool is_export);
+extern IntrusivePtr<zeek::detail::ID> install_ID(const char* name, const char* module_name,
+                                                 bool is_global, bool is_export);
 
-extern void push_scope(IntrusivePtr<ID> id,
+extern void push_scope(IntrusivePtr<zeek::detail::ID> id,
                        std::unique_ptr<std::vector<IntrusivePtr<Attr>>> attrs);
 extern void push_existing_scope(Scope* scope);
 
diff --git a/src/Stats.cc b/src/Stats.cc
index 39f645bf13..18cd383ca6 100644
--- a/src/Stats.cc
+++ b/src/Stats.cc
@@ -252,7 +252,7 @@ void ProfileLogger::Log()
 
 		for ( const auto& global : globals )
 			{
-			ID* id = global.second.get();
+			auto id = global.second;
 
 			// We don't show/count internal globals as they are always
 			// contained in some other global user-visible container.
diff --git a/src/Traverse.h b/src/Traverse.h
index 10b37c7385..ae91701fb5 100644
--- a/src/Traverse.h
+++ b/src/Traverse.h
@@ -6,10 +6,10 @@
 
 class Func;
 class Scope;
-class ID;
 
 FORWARD_DECLARE_NAMESPACED(Stmt, zeek::detail);
 FORWARD_DECLARE_NAMESPACED(Expr, zeek::detail);
+FORWARD_DECLARE_NAMESPACED(ID, zeek::detail);
 
 class TraversalCallback {
 public:
@@ -25,14 +25,14 @@ public:
 	virtual TraversalCode PreExpr(const zeek::detail::Expr*) { return TC_CONTINUE; }
 	virtual TraversalCode PostExpr(const zeek::detail::Expr*) { return TC_CONTINUE; }
 
-	virtual TraversalCode PreID(const ID*) { return TC_CONTINUE; }
-	virtual TraversalCode PostID(const ID*) { return TC_CONTINUE; }
+	virtual TraversalCode PreID(const zeek::detail::ID*) { return TC_CONTINUE; }
+	virtual TraversalCode PostID(const zeek::detail::ID*) { return TC_CONTINUE; }
 
-	virtual TraversalCode PreTypedef(const ID*) { return TC_CONTINUE; }
-	virtual TraversalCode PostTypedef(const ID*) { return TC_CONTINUE; }
+	virtual TraversalCode PreTypedef(const zeek::detail::ID*) { return TC_CONTINUE; }
+	virtual TraversalCode PostTypedef(const zeek::detail::ID*) { return TC_CONTINUE; }
 
-	virtual TraversalCode PreDecl(const ID*) { return TC_CONTINUE; }
-	virtual TraversalCode PostDecl(const ID*) { return TC_CONTINUE; }
+	virtual TraversalCode PreDecl(const zeek::detail::ID*) { return TC_CONTINUE; }
+	virtual TraversalCode PostDecl(const zeek::detail::ID*) { return TC_CONTINUE; }
 
 	Scope* current_scope;
 };
diff --git a/src/Trigger.cc b/src/Trigger.cc
index 2781270dd0..06c49a6c98 100644
--- a/src/Trigger.cc
+++ b/src/Trigger.cc
@@ -391,7 +391,7 @@ void Trigger::Timeout()
 	Unref(this);
 	}
 
-void Trigger::Register(ID* id)
+void Trigger::Register(zeek::detail::ID* id)
 	{
 	assert(! disabled);
 	notifier::registry.Register(id, this);
diff --git a/src/Trigger.h b/src/Trigger.h
index 7a20bf40ee..cf91b25cba 100644
--- a/src/Trigger.h
+++ b/src/Trigger.h
@@ -11,12 +11,12 @@
 
 class Frame;
 class Val;
-class ID;
 class ODesc;
 
 FORWARD_DECLARE_NAMESPACED(Stmt, zeek::detail);
 FORWARD_DECLARE_NAMESPACED(Expr, zeek::detail);
 FORWARD_DECLARE_NAMESPACED(CallExpr, zeek::detail);
+FORWARD_DECLARE_NAMESPACED(ID, zeek::detail);
 
 namespace trigger {
 // Triggers are the heart of "when" statements: expressions that when
@@ -89,7 +89,7 @@ private:
 	friend class TriggerTimer;
 
 	void Init();
-	void Register(ID* id);
+	void Register(zeek::detail::ID* id);
 	void Register(Val* val);
 	void UnregisterAll();
 
diff --git a/src/Val.cc b/src/Val.cc
index 31b906d18d..9dc120028e 100644
--- a/src/Val.cc
+++ b/src/Val.cc
@@ -379,12 +379,12 @@ void Val::ValDescribeReST(ODesc* d) const
 
 
 #ifdef DEBUG
-ID* Val::GetID() const
+zeek::detail::ID* Val::GetID() const
 	{
 	return bound_id ? global_scope()->Find(bound_id).get() : nullptr;
 	}
 
-void Val::SetID(ID* id)
+void Val::SetID(zeek::detail::ID* id)
 	{
 	delete [] bound_id;
 	bound_id = id ? copy_string(id->Name()) : nullptr;
diff --git a/src/Val.h b/src/Val.h
index 36e0114a31..45aa98f626 100644
--- a/src/Val.h
+++ b/src/Val.h
@@ -324,9 +324,9 @@ public:
 #ifdef DEBUG
 	// For debugging, we keep a reference to the global ID to which a
 	// value has been bound *last*.
-	ID* GetID() const;
+	zeek::detail::ID* GetID() const;
 
-	void SetID(ID* id);
+	void SetID(zeek::detail::ID* id);
 #endif
 
 	static bool WouldOverflow(const BroType* from_type, const BroType* to_type, const Val* val);
diff --git a/src/Var.cc b/src/Var.cc
index e751600096..bb8fda8975 100644
--- a/src/Var.cc
+++ b/src/Var.cc
@@ -30,7 +30,7 @@ static IntrusivePtr<Val> init_val(zeek::detail::Expr* init, const BroType* t,
 		}
 	}
 
-static bool add_prototype(const IntrusivePtr<ID>& id, BroType* t,
+static bool add_prototype(const IntrusivePtr<zeek::detail::ID>& id, BroType* t,
                           std::vector<IntrusivePtr<Attr>>* attrs,
                           const IntrusivePtr<zeek::detail::Expr>& init)
 	{
@@ -108,7 +108,8 @@ static bool add_prototype(const IntrusivePtr<ID>& id, BroType* t,
 	return true;
 	}
 
-static void make_var(const IntrusivePtr<ID>& id, IntrusivePtr<BroType> t, init_class c,
+static void make_var(const IntrusivePtr<zeek::detail::ID>& id, IntrusivePtr<BroType> t,
+                     zeek::detail::init_class c,
                      IntrusivePtr<zeek::detail::Expr> init,
                      std::unique_ptr<std::vector<IntrusivePtr<Attr>>> attr,
                      decl_type dt,
@@ -227,14 +228,14 @@ static void make_var(const IntrusivePtr<ID>& id, IntrusivePtr<BroType> t, init_c
 
 	if ( do_init )
 		{
-		if ( c == INIT_NONE && dt == VAR_REDEF && t->IsTable() &&
+		if ( c == zeek::detail::INIT_NONE && dt == VAR_REDEF && t->IsTable() &&
 		     init && init->Tag() == zeek::detail::EXPR_ASSIGN )
 			// e.g. 'redef foo["x"] = 1' is missing an init class, but the
 			// intention clearly isn't to overwrite entire existing table val.
-			c = INIT_EXTRA;
+			c = zeek::detail::INIT_EXTRA;
 
-		if ( init && ((c == INIT_EXTRA && id->GetAttr(ATTR_ADD_FUNC)) ||
-		              (c == INIT_REMOVE && id->GetAttr(ATTR_DEL_FUNC)) ))
+		if ( init && ((c == zeek::detail::INIT_EXTRA && id->GetAttr(ATTR_ADD_FUNC)) ||
+		              (c == zeek::detail::INIT_REMOVE && id->GetAttr(ATTR_DEL_FUNC)) ))
 			// Just apply the function.
 			id->SetVal(init, c);
 
@@ -301,22 +302,22 @@ static void make_var(const IntrusivePtr<ID>& id, IntrusivePtr<BroType> t, init_c
 		// For events, add a function value (without any body) here so that
 		// we can later access the ID even if no implementations have been
 		// defined.
-		std::vector<IntrusivePtr<ID>> inits;
+		std::vector<IntrusivePtr<zeek::detail::ID>> inits;
 		auto f = make_intrusive<BroFunc>(id, nullptr, inits, 0, 0);
 		id->SetVal(make_intrusive<Val>(std::move(f)));
 		}
 	}
 
-void add_global(const IntrusivePtr<ID>& id, IntrusivePtr<BroType> t,
-                init_class c, IntrusivePtr<zeek::detail::Expr> init,
+void add_global(const IntrusivePtr<zeek::detail::ID>& id, IntrusivePtr<BroType> t,
+                zeek::detail::init_class c, IntrusivePtr<zeek::detail::Expr> init,
                 std::unique_ptr<std::vector<IntrusivePtr<Attr>>> attr,
                 decl_type dt)
 	{
 	make_var(id, std::move(t), c, std::move(init), std::move(attr), dt, true);
 	}
 
-IntrusivePtr<zeek::detail::Stmt> add_local(IntrusivePtr<ID> id, IntrusivePtr<BroType> t,
-                             init_class c, IntrusivePtr<zeek::detail::Expr> init,
+IntrusivePtr<zeek::detail::Stmt> add_local(IntrusivePtr<zeek::detail::ID> id, IntrusivePtr<BroType> t,
+                             zeek::detail::init_class c, IntrusivePtr<zeek::detail::Expr> init,
                              std::unique_ptr<std::vector<IntrusivePtr<Attr>>> attr,
                              decl_type dt)
 	{
@@ -324,7 +325,7 @@ IntrusivePtr<zeek::detail::Stmt> add_local(IntrusivePtr<ID> id, IntrusivePtr<Bro
 
 	if ( init )
 		{
-		if ( c != INIT_FULL )
+		if ( c != zeek::detail::INIT_FULL )
 			id->Error("can't use += / -= for initializations of local variables");
 
 		// copy Location to the stack, because AssignExpr may free "init"
@@ -347,17 +348,17 @@ IntrusivePtr<zeek::detail::Stmt> add_local(IntrusivePtr<ID> id, IntrusivePtr<Bro
 		}
 	}
 
-extern IntrusivePtr<zeek::detail::Expr> add_and_assign_local(IntrusivePtr<ID> id,
+extern IntrusivePtr<zeek::detail::Expr> add_and_assign_local(IntrusivePtr<zeek::detail::ID> id,
                                                IntrusivePtr<zeek::detail::Expr> init,
                                                IntrusivePtr<Val> val)
 	{
-	make_var(id, nullptr, INIT_FULL, init, nullptr, VAR_REGULAR, false);
+	make_var(id, nullptr, zeek::detail::INIT_FULL, init, nullptr, VAR_REGULAR, false);
 	auto name_expr = make_intrusive<zeek::detail::NameExpr>(std::move(id));
 	return make_intrusive<zeek::detail::AssignExpr>(std::move(name_expr), std::move(init),
 	                                                false, std::move(val));
 	}
 
-void add_type(ID* id, IntrusivePtr<BroType> t,
+void add_type(zeek::detail::ID* id, IntrusivePtr<BroType> t,
               std::unique_ptr<std::vector<IntrusivePtr<Attr>>> attr)
 	{
 	std::string new_type_name = id->Name();
@@ -458,7 +459,7 @@ static bool canonical_arg_types_match(const FuncType* decl, const FuncType* impl
 	return true;
 	}
 
-void begin_func(IntrusivePtr<ID> id, const char* module_name,
+void begin_func(IntrusivePtr<zeek::detail::ID> id, const char* module_name,
                 function_flavor flavor, bool is_redef,
                 IntrusivePtr<FuncType> t,
                 std::unique_ptr<std::vector<IntrusivePtr<Attr>>> attrs)
diff --git a/src/Var.h b/src/Var.h
index 92805676b1..696fdb7a29 100644
--- a/src/Var.h
+++ b/src/Var.h
@@ -18,28 +18,28 @@ FORWARD_DECLARE_NAMESPACED(Expr, zeek::detail);
 
 typedef enum { VAR_REGULAR, VAR_CONST, VAR_REDEF, VAR_OPTION, } decl_type;
 
-extern void add_global(const IntrusivePtr<ID>& id,
+extern void add_global(const IntrusivePtr<zeek::detail::ID>& id,
                        IntrusivePtr<BroType> t,
-                       init_class c,
+                       zeek::detail::init_class c,
                        IntrusivePtr<zeek::detail::Expr> init,
                        std::unique_ptr<std::vector<IntrusivePtr<Attr>>> attr,
                        decl_type dt);
 
-extern IntrusivePtr<zeek::detail::Stmt> add_local(IntrusivePtr<ID> id,
+extern IntrusivePtr<zeek::detail::Stmt> add_local(IntrusivePtr<zeek::detail::ID> id,
                                                   IntrusivePtr<BroType> t,
-                                                  init_class c,
+                                                  zeek::detail::init_class c,
                                                   IntrusivePtr<zeek::detail::Expr> init,
                                                   std::unique_ptr<std::vector<IntrusivePtr<Attr>>> attr,
                                                   decl_type dt);
 
-extern IntrusivePtr<zeek::detail::Expr> add_and_assign_local(IntrusivePtr<ID> id,
+extern IntrusivePtr<zeek::detail::Expr> add_and_assign_local(IntrusivePtr<zeek::detail::ID> id,
                                                IntrusivePtr<zeek::detail::Expr> init,
                                                IntrusivePtr<Val> val = nullptr);
 
-extern void add_type(ID* id, IntrusivePtr<BroType> t,
+extern void add_type(zeek::detail::ID* id, IntrusivePtr<BroType> t,
                      std::unique_ptr<std::vector<IntrusivePtr<Attr>>> attr);
 
-extern void begin_func(IntrusivePtr<ID> id, const char* module_name,
+extern void begin_func(IntrusivePtr<zeek::detail::ID> id, const char* module_name,
                        function_flavor flavor, bool is_redef,
                        IntrusivePtr<FuncType> t,
                        std::unique_ptr<std::vector<IntrusivePtr<Attr>>> attrs = nullptr);
diff --git a/src/input/readers/config/Config.cc b/src/input/readers/config/Config.cc
index 2416ff7af0..a5f11f3fc5 100644
--- a/src/input/readers/config/Config.cc
+++ b/src/input/readers/config/Config.cc
@@ -31,7 +31,7 @@ Config::Config(ReaderFrontend *frontend) : ReaderBackend(frontend)
 
 	for ( const auto& entry : globals )
 		{
-		ID* id = entry.second.get();
+		auto id = entry.second;
 		if ( ! id->IsOption() )
 			continue;
 
diff --git a/src/option.bif b/src/option.bif
index f2024062c4..771095567a 100644
--- a/src/option.bif
+++ b/src/option.bif
@@ -7,7 +7,7 @@ module Option;
 #include "NetVar.h"
 #include "broker/Data.h"
 
-static bool call_option_handlers_and_set_value(StringVal* name, const IntrusivePtr<ID>& i,
+static bool call_option_handlers_and_set_value(StringVal* name, const IntrusivePtr<zeek::detail::ID>& i,
                                                IntrusivePtr<Val> val,
                                                StringVal* location)
 	{
diff --git a/src/parse.y b/src/parse.y
index d6e03551a8..91361fe6db 100644
--- a/src/parse.y
+++ b/src/parse.y
@@ -136,7 +136,7 @@ std::vector<int> saved_in_init;
 
 static Location func_hdr_location;
 EnumType *cur_enum_type = 0;
-static ID* cur_decl_type_id = 0;
+static zeek::detail::ID* cur_decl_type_id = 0;
 
 static void parser_new_enum (void)
 	{
@@ -149,7 +149,7 @@ static void parser_new_enum (void)
 		reporter->FatalError("incorrect syntax for enum type declaration");
 	}
 
-static void parser_redef_enum (ID *id)
+static void parser_redef_enum (zeek::detail::ID *id)
 	{
 	/* Redef an enum. id points to the enum to be redefined.
 	   Let cur_enum_type point to it. */
@@ -166,7 +166,7 @@ static void parser_redef_enum (ID *id)
 		}
 	}
 
-static void extend_record(ID* id, std::unique_ptr<type_decl_list> fields,
+static void extend_record(zeek::detail::ID* id, std::unique_ptr<type_decl_list> fields,
                           std::unique_ptr<std::vector<IntrusivePtr<Attr>>> attrs)
 	{
 	std::set<BroType*> types = BroType::GetAliases(id->Name());
@@ -232,9 +232,9 @@ static bool expr_is_table_type_name(const zeek::detail::Expr* expr)
 %union {
 	bool b;
 	char* str;
-	ID* id;
+	zeek::detail::ID* id;
 	id_list* id_l;
-	init_class ic;
+	zeek::detail::init_class ic;
 	Val* val;
 	RE_Matcher* re;
 	zeek::detail::Expr* expr;
@@ -1295,10 +1295,10 @@ opt_type:
 	;
 
 init_class:
-				{ $$ = INIT_NONE; }
-	|	'='		{ $$ = INIT_FULL; }
-	|	TOK_ADD_TO	{ $$ = INIT_EXTRA; }
-	|	TOK_REMOVE_FROM	{ $$ = INIT_REMOVE; }
+				{ $$ = zeek::detail::INIT_NONE; }
+	|	'='		{ $$ = zeek::detail::INIT_FULL; }
+	|	TOK_ADD_TO	{ $$ = zeek::detail::INIT_EXTRA; }
+	|	TOK_REMOVE_FROM	{ $$ = zeek::detail::INIT_REMOVE; }
 	;
 
 opt_init:
@@ -1658,7 +1658,7 @@ case_type_list:
 case_type:
 		TOK_TYPE type
 			{
-			$$ = new ID(0, SCOPE_FUNCTION, 0);
+			$$ = new zeek::detail::ID(0, zeek::detail::SCOPE_FUNCTION, 0);
 			$$->SetType({AdoptRef{}, $2});
 			}
 
@@ -1673,7 +1673,7 @@ case_type:
 			else
 				case_var = install_ID(name, current_module.c_str(), false, false);
 
-			add_local(case_var, std::move(type), INIT_NONE, nullptr, nullptr,
+			add_local(case_var, std::move(type), zeek::detail::INIT_NONE, nullptr, nullptr,
 			          VAR_REGULAR);
 			$$ = case_var.release();
 			}
diff --git a/src/zeek.bif b/src/zeek.bif
index d5083323ca..1b1f645701 100644
--- a/src/zeek.bif
+++ b/src/zeek.bif
@@ -1918,7 +1918,7 @@ function global_sizes%(%): var_sizes
 
 	for ( const auto& global : globals )
 		{
-		ID* id = global.second.get();
+		auto id = global.second;
 		if ( id->HasVal() )
 			{
 			auto id_name = make_intrusive<StringVal>(id->Name());
@@ -1946,7 +1946,7 @@ function global_ids%(%): id_table
 
 	for ( const auto& global : globals )
 		{
-		ID* id = global.second.get();
+		zeek::detail::ID* id = global.second.get();
 		static auto script_id = zeek::id::find_type<RecordType>("script_id");
 		auto rec = make_intrusive<RecordVal>(script_id);
 		rec->Assign(0, make_intrusive<StringVal>(type_name(id->GetType()->Tag())));
diff --git a/src/zeekygen/IdentifierInfo.cc b/src/zeekygen/IdentifierInfo.cc
index e31651f39e..ba8edbdd9f 100644
--- a/src/zeekygen/IdentifierInfo.cc
+++ b/src/zeekygen/IdentifierInfo.cc
@@ -11,7 +11,7 @@
 using namespace std;
 using namespace zeekygen;
 
-IdentifierInfo::IdentifierInfo(IntrusivePtr<ID> arg_id, ScriptInfo* script)
+IdentifierInfo::IdentifierInfo(IntrusivePtr<zeek::detail::ID> arg_id, ScriptInfo* script)
 	: Info(),
 	  comments(), id(std::move(arg_id)), initial_val(), redefs(), fields(),
 	  last_field_seen(), declaring_script(script)
@@ -31,7 +31,7 @@ IdentifierInfo::~IdentifierInfo()
 		delete it->second;
 	}
 
-void IdentifierInfo::AddRedef(const string& script, init_class ic,
+void IdentifierInfo::AddRedef(const string& script, zeek::detail::init_class ic,
                               IntrusivePtr<zeek::detail::Expr> init_expr, const vector<string>& comments)
 	{
 	Redefinition* redef = new Redefinition(script, ic, std::move(init_expr), comments);
@@ -141,7 +141,7 @@ time_t IdentifierInfo::DoGetModificationTime() const
 
 IdentifierInfo::Redefinition::Redefinition(
                        std::string arg_script,
-                       init_class arg_ic,
+                       zeek::detail::init_class arg_ic,
                        IntrusivePtr<zeek::detail::Expr> arg_expr,
                        std::vector<std::string> arg_comments)
 			: from_script(std::move(arg_script)),
diff --git a/src/zeekygen/IdentifierInfo.h b/src/zeekygen/IdentifierInfo.h
index fc75b3af18..5bb284d23d 100644
--- a/src/zeekygen/IdentifierInfo.h
+++ b/src/zeekygen/IdentifierInfo.h
@@ -32,7 +32,7 @@ public:
 	 * @param script The info object associated with the script in which \a id
 	 * is declared.
 	 */
-	IdentifierInfo(IntrusivePtr<ID> id, ScriptInfo* script);
+	IdentifierInfo(IntrusivePtr<zeek::detail::ID> id, ScriptInfo* script);
 
 	/**
 	 * Dtor.  Releases any references to script-level objects.
@@ -70,7 +70,7 @@ public:
 	 * @param init_expr The initialization expression used.
 	 * @param comments Comments associated with the redef statement.
 	 */
-	void AddRedef(const std::string& from_script, init_class ic,
+	void AddRedef(const std::string& from_script, zeek::detail::init_class ic,
 	              IntrusivePtr<zeek::detail::Expr> init_expr,
 	              const std::vector<std::string>& comments);
 
@@ -96,7 +96,7 @@ public:
 	/**
 	 * @return the script-level ID tracked by this info object.
 	 */
-	ID* GetID() const
+	zeek::detail::ID* GetID() const
 		{ return id.get(); }
 
 	/**
@@ -127,11 +127,11 @@ public:
 	 */
 	struct Redefinition {
 		std::string from_script; /**< Name of script doing the redef. */
-		init_class ic;
+		zeek::detail::init_class ic;
 		IntrusivePtr<zeek::detail::Expr> init_expr;
 		std::vector<std::string> comments; /**< Zeekygen comments on redef. */
 
-		Redefinition(std::string arg_script, init_class arg_ic,
+		Redefinition(std::string arg_script, zeek::detail::init_class arg_ic,
 		             IntrusivePtr<zeek::detail::Expr> arg_expr,
 		             std::vector<std::string> arg_comments);
 
@@ -174,7 +174,7 @@ private:
 	typedef std::map<std::string, RecordField*> record_field_map;
 
 	std::vector<std::string> comments;
-	IntrusivePtr<ID> id;
+	IntrusivePtr<zeek::detail::ID> id;
 	IntrusivePtr<Val> initial_val;
 	redef_list redefs;
 	record_field_map fields;
diff --git a/src/zeekygen/Manager.cc b/src/zeekygen/Manager.cc
index b1a6892b48..eab18fa6e1 100644
--- a/src/zeekygen/Manager.cc
+++ b/src/zeekygen/Manager.cc
@@ -27,7 +27,7 @@ static void DbgAndWarn(const char* msg)
 	DBG_LOG(DBG_ZEEKYGEN, "%s", msg);
 	}
 
-static void WarnMissingScript(const char* type, const ID* id,
+static void WarnMissingScript(const char* type, const zeek::detail::ID* id,
                               const string& script)
 	{
 	if ( script == "<command line>" )
@@ -216,7 +216,7 @@ void Manager::ModuleUsage(const string& path, const string& module)
 	        module.c_str(), name.c_str());
 	}
 
-IdentifierInfo* Manager::CreateIdentifierInfo(IntrusivePtr<ID> id, ScriptInfo* script)
+IdentifierInfo* Manager::CreateIdentifierInfo(IntrusivePtr<zeek::detail::ID> id, ScriptInfo* script)
 	{
 	const auto& id_name = id->Name();
 	auto prev = identifiers.GetInfo(id_name);
@@ -247,7 +247,7 @@ IdentifierInfo* Manager::CreateIdentifierInfo(IntrusivePtr<ID> id, ScriptInfo* s
 	return rval;
 	}
 
-void Manager::StartType(IntrusivePtr<ID> id)
+void Manager::StartType(IntrusivePtr<zeek::detail::ID> id)
 	{
 	if ( disabled )
 		return;
@@ -273,12 +273,12 @@ void Manager::StartType(IntrusivePtr<ID> id)
 	incomplete_type = CreateIdentifierInfo(std::move(id), script_info);
 	}
 
-static bool IsEnumType(ID* id)
+static bool IsEnumType(zeek::detail::ID* id)
 	{
 	return id->IsType() ? id->GetType()->Tag() == TYPE_ENUM : false;
 	}
 
-void Manager::Identifier(IntrusivePtr<ID> id)
+void Manager::Identifier(IntrusivePtr<zeek::detail::ID> id)
 	{
 	if ( disabled )
 		return;
@@ -337,7 +337,7 @@ void Manager::Identifier(IntrusivePtr<ID> id)
 	CreateIdentifierInfo(std::move(id), script_info);
 	}
 
-void Manager::RecordField(const ID* id, const TypeDecl* field,
+void Manager::RecordField(const zeek::detail::ID* id, const TypeDecl* field,
 			  const string& path)
 	{
 	if ( disabled )
@@ -360,8 +360,8 @@ void Manager::RecordField(const ID* id, const TypeDecl* field,
 	        field->id, id->Name(), script.c_str());
 	}
 
-void Manager::Redef(const ID* id, const string& path,
-	init_class ic, IntrusivePtr<zeek::detail::Expr> init_expr)
+void Manager::Redef(const zeek::detail::ID* id, const string& path,
+	zeek::detail::init_class ic, IntrusivePtr<zeek::detail::Expr> init_expr)
 	{
 	if ( disabled )
 		return;
@@ -397,8 +397,8 @@ void Manager::Redef(const ID* id, const string& path,
 	        id->Name(), from_script.c_str());
 	}
 
-void Manager::Redef(const ID* id, const std::string& path,
-                    init_class ic)
+void Manager::Redef(const zeek::detail::ID* id, const std::string& path,
+	zeek::detail::init_class ic)
 	{
 	Redef(id, path, ic, nullptr);
 	}
diff --git a/src/zeekygen/Manager.h b/src/zeekygen/Manager.h
index e45784cf51..fcac96204a 100644
--- a/src/zeekygen/Manager.h
+++ b/src/zeekygen/Manager.h
@@ -110,14 +110,14 @@ public:
 	 * Signal that a record or enum type is now being parsed.
 	 * @param id The record or enum type identifier.
 	 */
-	void StartType(IntrusivePtr<ID> id);
+	void StartType(IntrusivePtr<zeek::detail::ID> id);
 
 	/**
 	 * Register a script-level identifier for which information/documentation
 	 * will be gathered.
 	 * @param id The script-level identifier.
 	 */
-	void Identifier(IntrusivePtr<ID> id);
+	void Identifier(IntrusivePtr<zeek::detail::ID> id);
 
 	/**
 	 * Register a record-field for which information/documentation will be
@@ -128,7 +128,7 @@ public:
 	 * declared.  This can be different from the place where the record type
 	 * is declared due to redefs.
 	 */
-	void RecordField(const ID* id, const TypeDecl* field,
+	void RecordField(const zeek::detail::ID* id, const TypeDecl* field,
 	                 const std::string& path);
 
 	/**
@@ -138,10 +138,10 @@ public:
 	 * @param ic The initialization class that was used (e.g. =, +=, -=).
 	 * @param init_expr The intiialization expression that was used.
 	 */
-	void Redef(const ID* id, const std::string& path,
-		init_class ic, IntrusivePtr<zeek::detail::Expr> init_expr);
-	void Redef(const ID* id, const std::string& path,
-	           init_class ic = INIT_NONE);
+	void Redef(const zeek::detail::ID* id, const std::string& path,
+		zeek::detail::init_class ic, IntrusivePtr<zeek::detail::Expr> init_expr);
+	void Redef(const zeek::detail::ID* id, const std::string& path,
+		zeek::detail::init_class ic = zeek::detail::INIT_NONE);
 
 	/**
 	 * Register Zeekygen script summary content.
@@ -217,7 +217,7 @@ private:
 	typedef std::vector<std::string> comment_buffer_t;
 	typedef std::map<std::string, comment_buffer_t> comment_buffer_map_t;
 
-	IdentifierInfo* CreateIdentifierInfo(IntrusivePtr<ID> id, ScriptInfo* script);
+	IdentifierInfo* CreateIdentifierInfo(IntrusivePtr<zeek::detail::ID> id, ScriptInfo* script);
 
 	bool disabled;
 	comment_buffer_t comment_buffer; // For whatever next identifier comes in.
diff --git a/src/zeekygen/ScriptInfo.cc b/src/zeekygen/ScriptInfo.cc
index ddd0d8009c..4b630e6e6a 100644
--- a/src/zeekygen/ScriptInfo.cc
+++ b/src/zeekygen/ScriptInfo.cc
@@ -82,7 +82,7 @@ static string make_summary(const string& heading, char underline, char border,
 	for ( id_info_list::const_iterator it = id_list.begin();
 	      it != id_list.end(); ++it )
 		{
-		ID* id = (*it)->GetID();
+		auto* id = (*it)->GetID();
 		ODesc d;
 		d.SetQuotes(true);
 		id->DescribeReSTShort(&d);
@@ -105,7 +105,7 @@ static string make_redef_summary(const string& heading, char underline,
 	for ( id_info_set::const_iterator it = id_set.begin(); it != id_set.end();
 	      ++it )
 		{
-		ID* id = (*it)->GetID();
+		auto* id = (*it)->GetID();
 		ODesc d;
 		d.SetQuotes(true);
 		id->DescribeReSTShort(&d);
@@ -179,7 +179,7 @@ void ScriptInfo::DoInitPostScript()
 	      it != id_info.end(); ++it )
 		{
 		IdentifierInfo* info = it->second;
-		ID* id = info->GetID();
+		auto* id = info->GetID();
 
 		if ( ! zeekygen::is_public_api(id) )
 			continue;
diff --git a/src/zeekygen/utils.cc b/src/zeekygen/utils.cc
index c661b84539..fb016270b4 100644
--- a/src/zeekygen/utils.cc
+++ b/src/zeekygen/utils.cc
@@ -78,10 +78,10 @@ bool zeekygen::prettify_params(string& s)
 	return false;
 	}
 
-bool zeekygen::is_public_api(const ID* id)
+bool zeekygen::is_public_api(const zeek::detail::ID* id)
 	{
-	return (id->Scope() == SCOPE_GLOBAL) ||
-	       (id->Scope() == SCOPE_MODULE && id->IsExport());
+	return (id->Scope() == zeek::detail::SCOPE_GLOBAL) ||
+	       (id->Scope() == zeek::detail::SCOPE_MODULE && id->IsExport());
 	}
 
 time_t zeekygen::get_mtime(const string& filename)
diff --git a/src/zeekygen/utils.h b/src/zeekygen/utils.h
index e5ddcc49a4..3bf79101b0 100644
--- a/src/zeekygen/utils.h
+++ b/src/zeekygen/utils.h
@@ -6,7 +6,8 @@
 
 #include <time.h> // for time_t
 
-class ID;
+namespace zeek::detail { class ID; }
+using ID [[deprecated("Remove in v4.1. Use zeek::detail::ID instead")]] = zeek::detail::ID;
 
 namespace zeekygen {
 
@@ -25,7 +26,7 @@ bool prettify_params(std::string& s);
  * @return true if the ID is in the global scope or if it's exported in to
  * any modules namespace.
  */
-bool is_public_api(const ID* id);
+bool is_public_api(const zeek::detail::ID* id);
 
 /**
  * Get the modification time of a file or abort if there's an error.