diff --git a/source/ps/ArchiveBuilder.h b/source/ps/ArchiveBuilder.h
index 3e578e6345..f856a283fa 100644
--- a/source/ps/ArchiveBuilder.h
+++ b/source/ps/ArchiveBuilder.h
@@ -1,4 +1,4 @@
-/* Copyright (C) 2014 Wildfire Games.
+/* Copyright (C) 2025 Wildfire Games.
  * This file is part of 0 A.D.
  *
  * 0 A.D. is free software: you can redistribute it and/or modify
@@ -19,7 +19,15 @@
 #define INCLUDED_ARCHIVEBUILDER
 
 #include "lib/file/vfs/vfs.h"
-#include "ps/CStr.h"
+#include "lib/file/vfs/vfs_path.h"
+#include "lib/os_path.h"
+#include "lib/status.h"
+
+#include <cstddef>
+#include <cstdint>
+#include <vector>
+
+class CFileInfo;
 
 /**
  * Packages a mod's files into a distributable archive.
diff --git a/source/ps/CConsole.h b/source/ps/CConsole.h
index ea5ed41d4b..767523c102 100644
--- a/source/ps/CConsole.h
+++ b/source/ps/CConsole.h
@@ -22,9 +22,11 @@
 #ifndef INCLUDED_CCONSOLE
 #define INCLUDED_CCONSOLE
 
+#include "lib/code_annotation.h"
 #include "lib/file/vfs/vfs_path.h"
 #include "lib/input.h"
 
+#include <cstddef>
 #include <deque>
 #include <memory>
 #include <mutex>
@@ -32,6 +34,7 @@
 
 class CCanvas2D;
 class CTextRenderer;
+struct SDL_Event_;
 
 /**
  * In-game console.
diff --git a/source/ps/CacheLoader.h b/source/ps/CacheLoader.h
index 9580e36ef5..c77d3a24ea 100644
--- a/source/ps/CacheLoader.h
+++ b/source/ps/CacheLoader.h
@@ -1,4 +1,4 @@
-/* Copyright (C) 2018 Wildfire Games.
+/* Copyright (C) 2025 Wildfire Games.
  * This file is part of 0 A.D.
  *
  * 0 A.D. is free software: you can redistribute it and/or modify
@@ -19,6 +19,11 @@
 #define INCLUDED_CACHELOADER
 
 #include "lib/file/vfs/vfs.h"
+#include "lib/file/vfs/vfs_path.h"
+#include "lib/status.h"
+#include "lib/types.h"
+
+#include <string>
 
 class MD5;
 
diff --git a/source/ps/ConfigDB.h b/source/ps/ConfigDB.h
index 478e7d1941..62dcf2d6a0 100644
--- a/source/ps/ConfigDB.h
+++ b/source/ps/ConfigDB.h
@@ -28,6 +28,7 @@
 #define INCLUDED_CONFIGDB
 
 #include "lib/file/vfs/vfs_path.h"
+#include "lib/types.h"
 #include "ps/CStr.h"
 
 #include <array>
@@ -35,8 +36,8 @@
 #include <map>
 #include <memory>
 #include <mutex>
+#include <string>
 #include <string_view>
-#include <type_traits>
 #include <utility>
 #include <vector>
 
@@ -65,8 +66,6 @@ using CConfigValueSet = std::vector<CStr>;
 // Actually defined below - requires access to CConfigDB.
 class CConfigDBHook;
 
-#define g_ConfigDB (*CConfigDB::Instance())
-
 class CConfigDB
 {
 	friend CConfigDBHook;
@@ -109,7 +108,7 @@ public:
 	[[nodiscard]] static T GetIfInitialised(const std::string_view name, T defaultValue,
 		const EConfigNamespace ns = CFG_USER)
 	{
-		return IsInitialised() ? g_ConfigDB.Get(name, std::move(defaultValue), ns) : defaultValue;
+		return IsInitialised() ? Instance()->Get(name, std::move(defaultValue), ns) : defaultValue;
 	}
 
 	/**
@@ -253,4 +252,7 @@ private:
 	std::multimap<CStr, std::function<void()>>::iterator m_Ptr;
 	CConfigDB& m_ConfigDB;
 };
+
+#define g_ConfigDB (*CConfigDB::Instance())
+
 #endif // INCLUDED_CONFIGDB
diff --git a/source/ps/FileIo.h b/source/ps/FileIo.h
index 45e608b9e0..0ed15a2357 100644
--- a/source/ps/FileIo.h
+++ b/source/ps/FileIo.h
@@ -1,4 +1,4 @@
-/* Copyright (C) 2021 Wildfire Games.
+/* Copyright (C) 2025 Wildfire Games.
  * This file is part of 0 A.D.
  *
  * 0 A.D. is free software: you can redistribute it and/or modify
@@ -30,10 +30,15 @@
 #ifndef INCLUDED_FILEPACKER
 #define INCLUDED_FILEPACKER
 
+#include "lib/file/io/write_buffer.h"
 #include "lib/file/vfs/vfs_path.h"
-#include "ps/CStrForward.h"
+#include "lib/types.h"
 #include "ps/Errors.h"
-#include "ps/Filesystem.h"	// WriteBuffer
+
+#include <cstddef>
+#include <memory>
+
+class CStr8;
 
 ERROR_GROUP(File);
 ERROR_TYPE(File, OpenFailed);
diff --git a/source/ps/Filesystem.h b/source/ps/Filesystem.h
index 44d2fa6abd..b0d809d5a5 100644
--- a/source/ps/Filesystem.h
+++ b/source/ps/Filesystem.h
@@ -18,12 +18,17 @@
 #ifndef INCLUDED_PS_FILESYSTEM
 #define INCLUDED_PS_FILESYSTEM
 
-#include "lib/file/file.h"
-#include "lib/file/io/write_buffer.h"
-#include "lib/file/vfs/vfs_util.h"
-#include "ps/CStrForward.h"
+#include "lib/file/vfs/vfs.h"
+#include "lib/file/vfs/vfs_path.h"
+#include "lib/status.h"
+#include "lib/types.h"
 #include "ps/Errors.h"
 
+#include <cstddef>
+#include <memory>
+
+class CStr8;
+
 extern PIVFS g_VFS;
 
 extern bool VfsFileExists(const VfsPath& pathname);
diff --git a/source/ps/Future.h b/source/ps/Future.h
index c47d2b06ea..984ff12b95 100644
--- a/source/ps/Future.h
+++ b/source/ps/Future.h
@@ -18,12 +18,10 @@
 #ifndef INCLUDED_FUTURE
 #define INCLUDED_FUTURE
 
-#include "ps/FutureForward.h"
-
 #include <atomic>
 #include <condition_variable>
 #include <exception>
-#include <functional>
+#include <memory>
 #include <mutex>
 #include <type_traits>
 #include <utility>
diff --git a/source/ps/FutureForward.h b/source/ps/FutureForward.h
deleted file mode 100644
index d84ce02e55..0000000000
--- a/source/ps/FutureForward.h
+++ /dev/null
@@ -1,29 +0,0 @@
-/* Copyright (C) 2021 Wildfire Games.
- * This file is part of 0 A.D.
- *
- * 0 A.D. is free software: you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation, either version 2 of the License, or
- * (at your option) any later version.
- *
- * 0 A.D. is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with 0 A.D.  If not, see <http://www.gnu.org/licenses/>.
- */
-
-#ifndef INCLUDED_FUTURE_FORWARD
-#define INCLUDED_FUTURE_FORWARD
-
-/**
- * Lightweight header / forward declarations for Future.
- * Include this in your header files where possible.
- */
-
-template<typename Ret>
-class Future;
-
-#endif // INCLUDED_FUTURE_FORWARD
diff --git a/source/ps/Game.cpp b/source/ps/Game.cpp
index 5c76f5624f..2d9a98696e 100644
--- a/source/ps/Game.cpp
+++ b/source/ps/Game.cpp
@@ -49,8 +49,7 @@
 #include "simulation2/Simulation2.h"
 #include "simulation2/components/ICmpPlayer.h"
 #include "simulation2/components/ICmpPlayerManager.h"
-#include "simulation2/system/CmpPtr.h"
-#include "simulation2/system/Components.h"
+#include "simulation2/system/Component.h"
 #include "simulation2/system/Entity.h"
 #include "simulation2/system/LocalTurnManager.h"
 #include "simulation2/system/ReplayTurnManager.h"
@@ -66,8 +65,6 @@
 #include <sstream>
 #include <utility>
 
-class IComponent;
-
 extern GameLoopState* g_AtlasGameLoop;
 
 /**
diff --git a/source/ps/Game.h b/source/ps/Game.h
index 9dd390802c..545486f228 100644
--- a/source/ps/Game.h
+++ b/source/ps/Game.h
@@ -1,4 +1,4 @@
-/* Copyright (C) 2024 Wildfire Games.
+/* Copyright (C) 2025 Wildfire Games.
  * This file is part of 0 A.D.
  *
  * 0 A.D. is free software: you can redistribute it and/or modify
@@ -18,13 +18,19 @@
 #ifndef INCLUDED_GAME
 #define INCLUDED_GAME
 
-#include "graphics/Color.h"
+#include "lib/code_annotation.h"
+#include "lib/os_path.h"
+#include "lib/types.h"
 #include "ps/CStr.h"
 #include "ps/Errors.h"
-#include "lib/os_path.h"
 #include "scriptinterface/ScriptTypes.h"
 #include "simulation2/helpers/Player.h"
 
+#include <algorithm>
+#include <cmath>
+#include <iosfwd>
+#include <js/TypeDecls.h>
+#include <string>
 #include <vector>
 
 class CGameView;
@@ -32,6 +38,7 @@ class CSimulation2;
 class CTurnManager;
 class CWorld;
 class IReplayLogger;
+struct CColor;
 
 /**
  * The container that holds the rules, resources and attributes of the game.
diff --git a/source/ps/GameSetup/CmdLineArgs.h b/source/ps/GameSetup/CmdLineArgs.h
index 5b0e3aa10f..e76be3c5fd 100644
--- a/source/ps/GameSetup/CmdLineArgs.h
+++ b/source/ps/GameSetup/CmdLineArgs.h
@@ -1,4 +1,4 @@
-/* Copyright (C) 2023 Wildfire Games.
+/* Copyright (C) 2025 Wildfire Games.
  * This file is part of 0 A.D.
  *
  * 0 A.D. is free software: you can redistribute it and/or modify
@@ -19,14 +19,12 @@
 #define INCLUDED_CMDLINEARGS
 
 #include "lib/os_path.h"
-#include "ps/containers/Span.h"
 #include "ps/CStr.h"
 
 #include <utility>
 #include <vector>
 
-class ScriptRequest;
-
+namespace PS { template <typename T> class span; }
 
 class CmdLineArgs
 {
diff --git a/source/ps/GameSetup/Config.h b/source/ps/GameSetup/Config.h
index 9ad6e604ec..091e22dc7b 100644
--- a/source/ps/GameSetup/Config.h
+++ b/source/ps/GameSetup/Config.h
@@ -1,4 +1,4 @@
-/* Copyright (C) 2021 Wildfire Games.
+/* Copyright (C) 2025 Wildfire Games.
  * This file is part of 0 A.D.
  *
  * 0 A.D. is free software: you can redistribute it and/or modify
@@ -18,8 +18,6 @@
 #ifndef INCLUDED_PS_GAMESETUP_CONFIG
 #define INCLUDED_PS_GAMESETUP_CONFIG
 
-#include "ps/CStr.h"
-
 // flag to pause the game on window focus loss
 extern bool g_PauseOnFocusLoss;
 
diff --git a/source/ps/GameSetup/GameSetup.cpp b/source/ps/GameSetup/GameSetup.cpp
index 66dc0bff2b..c72f74135c 100644
--- a/source/ps/GameSetup/GameSetup.cpp
+++ b/source/ps/GameSetup/GameSetup.cpp
@@ -73,6 +73,7 @@
 #include "ps/VideoMode.h"
 #include "ps/World.h"
 #include "ps/XMB/XMBData.h"
+#include "ps/XMB/XMBStorage.h"
 #include "ps/XML/Xeromyces.h"
 #include "ps/scripting/JSInterface_Game.h"
 #include "ps/scripting/JSInterface_Main.h"
@@ -89,7 +90,7 @@
 #include "scriptinterface/ScriptStats.h"
 #include "simulation2/Simulation2.h"
 #include "simulation2/scripting/JSInterface_Simulation.h"
-#include "simulation2/system/ParamNode.h"
+#include "simulation2/system/Component.h"
 #include "soundmanager/ISoundManager.h"
 
 #include <SDL.h>
diff --git a/source/ps/GameSetup/Paths.h b/source/ps/GameSetup/Paths.h
index e21bb2703e..df5e11f658 100644
--- a/source/ps/GameSetup/Paths.h
+++ b/source/ps/GameSetup/Paths.h
@@ -1,4 +1,4 @@
-/* Copyright (C) 2012 Wildfire Games.
+/* Copyright (C) 2025 Wildfire Games.
  * This file is part of 0 A.D.
  *
  * 0 A.D. is free software: you can redistribute it and/or modify
@@ -19,7 +19,8 @@
 #define INCLUDED_PS_GAMESETUP_PATHS
 
 #include "lib/os_path.h"
-#include "CmdLineArgs.h"
+
+class CmdLineArgs;
 
 /**
  * Wrapper class for OS paths used by the game
diff --git a/source/ps/Globals.h b/source/ps/Globals.h
index 3820413359..ef504e6e6c 100644
--- a/source/ps/Globals.h
+++ b/source/ps/Globals.h
@@ -1,4 +1,4 @@
-/* Copyright (C) 2017 Wildfire Games.
+/* Copyright (C) 2025 Wildfire Games.
  * This file is part of 0 A.D.
  *
  * 0 A.D. is free software: you can redistribute it and/or modify
@@ -18,12 +18,15 @@
 #ifndef INCLUDED_PS_GLOBALS
 #define INCLUDED_PS_GLOBALS
 
-#include "lib/input.h"
 #include "lib/frequency_filter.h"
+#include "lib/input.h"
 #include "ps/KeyName.h"
 
+#include <cstdint>
 #include <unordered_map>
 
+struct SDL_Event_;
+
 // thin abstraction layer on top of SDL.
 // game code should use it instead of SDL_GetMouseState etc. because
 // Atlas does not completely emulate SDL (it can only send events).
diff --git a/source/ps/Hotkey.h b/source/ps/Hotkey.h
index d47f477d7f..b407e9c5a4 100644
--- a/source/ps/Hotkey.h
+++ b/source/ps/Hotkey.h
@@ -31,13 +31,16 @@
  * triggered. All with the hotkey name stored in ev.user.data1 as a const char*.
  */
 
-#include "CStr.h"
 #include "lib/input.h"
+#include "lib/types.h"
+#include "ps/CStr.h"
 #include "ps/containers/StaticVector.h"
 
 #include <unordered_map>
 #include <vector>
 
+struct SDL_Event_;
+
 // SDL_Scancode is an enum, we'll use an explicit int to avoid including SDL in this header.
 using SDL_Scancode_ = int;
 
diff --git a/source/ps/Joystick.h b/source/ps/Joystick.h
index e123b6b5bf..c284f81720 100644
--- a/source/ps/Joystick.h
+++ b/source/ps/Joystick.h
@@ -1,4 +1,4 @@
-/* Copyright (C) 2012 Wildfire Games.
+/* Copyright (C) 2025 Wildfire Games.
  * This file is part of 0 A.D.
  *
  * 0 A.D. is free software: you can redistribute it and/or modify
@@ -18,7 +18,7 @@
 #ifndef INCLUDED_JOYSTICK
 #define INCLUDED_JOYSTICK
 
-#include "lib/external_libraries/libsdl.h"
+#include <SDL_joystick.h>
 
 class CJoystick
 {
diff --git a/source/ps/KeyName.h b/source/ps/KeyName.h
index 61c4c1a80b..985c3ef0a3 100644
--- a/source/ps/KeyName.h
+++ b/source/ps/KeyName.h
@@ -1,4 +1,4 @@
-/* Copyright (C) 2021 Wildfire Games.
+/* Copyright (C) 2025 Wildfire Games.
  * This file is part of 0 A.D.
  *
  * 0 A.D. is free software: you can redistribute it and/or modify
@@ -18,9 +18,10 @@
 #ifndef INCLUDED_KEYNAME
 #define INCLUDED_KEYNAME
 
-// Need SDLK_* enum values.
-#include "lib/external_libraries/libsdl.h"
-#include "ps/CStr.h"
+#include <SDL_mouse.h>
+#include <SDL_scancode.h>
+
+class CStr8;
 
 extern SDL_Scancode FindScancode(const CStr8& keyname);
 // Map a scancode to a locale-independent scancode name.
diff --git a/source/ps/Loader.h b/source/ps/Loader.h
index bd93d249e0..d8a8d821d3 100644
--- a/source/ps/Loader.h
+++ b/source/ps/Loader.h
@@ -21,10 +21,11 @@
 #ifndef INCLUDED_LOADER
 #define INCLUDED_LOADER
 
+#include "lib/debug.h"
 #include "lib/status.h"
 
+#include <cstddef>
 #include <functional>
-#include <wchar.h>
 
 /*
 
diff --git a/source/ps/Mod.h b/source/ps/Mod.h
index 97654b3c51..a9fb9a5eff 100644
--- a/source/ps/Mod.h
+++ b/source/ps/Mod.h
@@ -1,4 +1,4 @@
-/* Copyright (C) 2021 Wildfire Games.
+/* Copyright (C) 2025 Wildfire Games.
  * This file is part of 0 A.D.
  *
  * 0 A.D. is free software: you can redistribute it and/or modify
@@ -19,10 +19,11 @@
 #define INCLUDED_MOD
 
 #include "ps/CStr.h"
-#include "scriptinterface/ScriptForward.h"
 
 #include <vector>
 
+class ScriptInterface;
+
 #define g_Mods (Mod::Instance())
 
 class Mod
diff --git a/source/ps/ModInstaller.h b/source/ps/ModInstaller.h
index 1f8236ca32..e666bf0ff7 100644
--- a/source/ps/ModInstaller.h
+++ b/source/ps/ModInstaller.h
@@ -1,4 +1,4 @@
-/* Copyright (C) 2022 Wildfire Games.
+/* Copyright (C) 2025 Wildfire Games.
  * This file is part of 0 A.D.
  *
  * 0 A.D. is free software: you can redistribute it and/or modify
@@ -18,9 +18,11 @@
 #ifndef INCLUDED_MODINSTALLER
 #define INCLUDED_MODINSTALLER
 
-#include "CStr.h"
 #include "lib/file/vfs/vfs.h"
-
+#include "lib/file/vfs/vfs_path.h"
+#include "lib/os_path.h"
+#include "lib/path.h"
+#include "ps/CStr.h"
 #include <memory>
 #include <vector>
 
diff --git a/source/ps/ModIo.h b/source/ps/ModIo.h
index 3bfd83c319..7df4c92076 100644
--- a/source/ps/ModIo.h
+++ b/source/ps/ModIo.h
@@ -1,4 +1,4 @@
-/* Copyright (C) 2021 Wildfire Games.
+/* Copyright (C) 2025 Wildfire Games.
  *
  * Permission is hereby granted, free of charge, to any person obtaining
  * a copy of this software and associated documentation files (the
@@ -23,15 +23,19 @@
 #ifndef INCLUDED_MODIO
 #define INCLUDED_MODIO
 
+#include "lib/code_annotation.h"
 #include "lib/external_libraries/curl.h"
 #include "lib/os_path.h"
-#include "scriptinterface/ScriptForward.h"
+#include "lib/types.h"
 
+#include <cstddef>
 #include <map>
 #include <sodium.h>
 #include <string>
 #include <vector>
 
+class ScriptInterface;
+
 // TODO: Allocate instance of the below two using sodium_malloc?
 struct PKStruct
 {
diff --git a/source/ps/Profile.h b/source/ps/Profile.h
index b01988ed61..d903f96c08 100644
--- a/source/ps/Profile.h
+++ b/source/ps/Profile.h
@@ -22,20 +22,18 @@
 #ifndef INCLUDED_PROFILE
 #define INCLUDED_PROFILE
 
-#include <vector>
-
 #include "lib/adts/ring_buf.h"
-#include "lib/posix/posix_pthread.h"
+#include "lib/code_annotation.h"
 #include "ps/Profiler2.h"
 #include "ps/Singleton.h"
 
+#include <vector>
+
+class CProfileNodeTable;
 
 #define PROFILE_AMORTIZE_FRAMES 30
 #define PROFILE_AMORTIZE_TURNS 5
 
-class CProfileManager;
-class CProfileNodeTable;
-
 // To profile scripts usefully, we use a call hook that's called on every enter/exit,
 // and need to find the function name. But most functions are anonymous so we make do
 // with filename plus line number instead.
diff --git a/source/ps/ProfileViewer.h b/source/ps/ProfileViewer.h
index 6aa9bc01e6..e119e1e061 100644
--- a/source/ps/ProfileViewer.h
+++ b/source/ps/ProfileViewer.h
@@ -26,9 +26,11 @@
 #include "ps/CStr.h"
 #include "ps/Singleton.h"
 
+#include <cstddef>
 #include <vector>
 
 class CCanvas2D;
+struct SDL_Event_;
 
 /**
  * Struct ProfileColumn: Describes one column of an AbstractProfileTable.
diff --git a/source/ps/Profiler2.h b/source/ps/Profiler2.h
index d10a07a092..612675cf9f 100644
--- a/source/ps/Profiler2.h
+++ b/source/ps/Profiler2.h
@@ -78,31 +78,27 @@
 #ifndef INCLUDED_PROFILER2
 #define INCLUDED_PROFILER2
 
+#include "lib/code_annotation.h"
+#include "lib/debug.h"
 #include "lib/timer.h"
+#include "lib/types.h"
 #include "ps/ThreadUtil.h"
 
 #include <cstdarg>
 #include <cstring>
+#include <iosfwd>
+#include <memory>
 #include <mutex>
 #include <string>
-#include <thread>
 #include <vector>
 
-namespace Renderer
-{
-namespace Backend
-{
-class IDeviceCommandContext;
-}
-}
-
+class CProfiler2GPU;
+namespace Renderer::Backend { class IDeviceCommandContext; }
 struct mg_context;
 
 // Note: Lots of functions are defined inline, to hypothetically
 // minimise performance overhead.
 
-class CProfiler2GPU;
-
 class CProfiler2
 {
 	friend class CProfiler2GPUImpl;
diff --git a/source/ps/Replay.cpp b/source/ps/Replay.cpp
index a6534a87a1..58ec6a6b09 100644
--- a/source/ps/Replay.cpp
+++ b/source/ps/Replay.cpp
@@ -50,7 +50,7 @@
 #include "simulation2/components/ICmpGuiInterface.h"
 #include "simulation2/helpers/Player.h"
 #include "simulation2/helpers/SimulationCommand.h"
-#include "simulation2/system/CmpPtr.h"
+#include "simulation2/system/Component.h"
 #include "simulation2/system/Entity.h"
 
 #include <ctime>
diff --git a/source/ps/Replay.h b/source/ps/Replay.h
index 54cfbd5610..a640399005 100644
--- a/source/ps/Replay.h
+++ b/source/ps/Replay.h
@@ -18,15 +18,20 @@
 #ifndef INCLUDED_REPLAY
 #define INCLUDED_REPLAY
 
+#include "lib/code_annotation.h"
 #include "lib/os_path.h"
-#include "ps/CStr.h"
+#include "lib/types.h"
 #include "scriptinterface/ScriptTypes.h"
 
+#include <iosfwd>
+#include <js/RootingAPI.h>
+#include <js/TypeDecls.h>
+#include <string>
 #include <vector>
 
-struct SimulationCommand;
 class CSimulation2;
 class ScriptInterface;
+struct SimulationCommand;
 
 /**
  * Replay log recorder interface.
diff --git a/source/ps/SavedGame.cpp b/source/ps/SavedGame.cpp
index 9b1090b103..316acfff5a 100644
--- a/source/ps/SavedGame.cpp
+++ b/source/ps/SavedGame.cpp
@@ -36,6 +36,7 @@
 #include "lib/types.h"
 #include "maths/Vector3D.h"
 #include "ps/CLogger.h"
+#include "ps/CStr.h"
 #include "ps/Filesystem.h"
 #include "ps/Game.h"
 #include "ps/Mod.h"
diff --git a/source/ps/SavedGame.h b/source/ps/SavedGame.h
index 3c0ca10ae4..e3632e5757 100644
--- a/source/ps/SavedGame.h
+++ b/source/ps/SavedGame.h
@@ -19,13 +19,16 @@
 #define INCLUDED_SAVEDGAME
 
 #include "lib/status.h"
-#include "ps/CStr.h"
 #include "scriptinterface/ScriptTypes.h"
 #include "scriptinterface/StructuredClone.h"
 
+#include <js/Value.h>
 #include <optional>
+#include <string>
 
 class CSimulation2;
+class CStrW;
+class ScriptInterface;
 
 /**
  * @file
diff --git a/source/ps/TaskManager.h b/source/ps/TaskManager.h
index 04b3d00d08..9cf868191f 100644
--- a/source/ps/TaskManager.h
+++ b/source/ps/TaskManager.h
@@ -1,4 +1,4 @@
-/* Copyright (C) 2024 Wildfire Games.
+/* Copyright (C) 2025 Wildfire Games.
  * This file is part of 0 A.D.
  *
  * 0 A.D. is free software: you can redistribute it and/or modify
@@ -21,8 +21,11 @@
 #include "ps/Future.h"
 #include "ps/Singleton.h"
 
+#include <cstddef>
+#include <functional>
 #include <memory>
-#include <vector>
+#include <type_traits>
+#include <utility>
 
 namespace Threading
 {
diff --git a/source/ps/TemplateLoader.h b/source/ps/TemplateLoader.h
index 5ac829943d..6ff7ca3fb5 100644
--- a/source/ps/TemplateLoader.h
+++ b/source/ps/TemplateLoader.h
@@ -1,4 +1,4 @@
-/* Copyright (C) 2022 Wildfire Games.
+/* Copyright (C) 2025 Wildfire Games.
  * This file is part of 0 A.D.
  *
  * 0 A.D. is free software: you can redistribute it and/or modify
@@ -18,10 +18,12 @@
 #ifndef INCLUDED_TEMPLATELOADER
 #define INCLUDED_TEMPLATELOADER
 
-#include "simulation2/system/ParamNode.h"
+#include "simulation2/system/Component.h"
 
+#include <string>
 #include <string_view>
 #include <unordered_map>
+#include <vector>
 
 enum ETemplatesType
 {
diff --git a/source/ps/Threading.h b/source/ps/Threading.h
index 93dcbcb6ab..c87bd54af5 100644
--- a/source/ps/Threading.h
+++ b/source/ps/Threading.h
@@ -1,4 +1,4 @@
-/* Copyright (C) 2021 Wildfire Games.
+/* Copyright (C) 2025 Wildfire Games.
  * This file is part of 0 A.D.
  *
  * 0 A.D. is free software: you can redistribute it and/or modify
@@ -18,7 +18,7 @@
 #ifndef INCLUDED_THREADING
 #define INCLUDED_THREADING
 
-#include "ThreadUtil.h"
+#include "lib/sysdep/os.h"
 
 #if OS_WIN
 #include "lib/sysdep/os/win/wseh.h"
diff --git a/source/ps/TouchInput.h b/source/ps/TouchInput.h
index d7277cca29..d0475bd6a3 100644
--- a/source/ps/TouchInput.h
+++ b/source/ps/TouchInput.h
@@ -1,4 +1,4 @@
-/* Copyright (C) 2012 Wildfire Games.
+/* Copyright (C) 2025 Wildfire Games.
  * This file is part of 0 A.D.
  *
  * 0 A.D. is free software: you can redistribute it and/or modify
@@ -22,6 +22,10 @@
 #include "maths/Vector2D.h"
 #include "maths/Vector3D.h"
 
+#include <cstddef>
+
+struct SDL_Event_;
+
 /**
  * Maps touch events (e.g. on Android touchscreen devices) onto mouse events
  * and camera movement.
diff --git a/source/ps/Util.h b/source/ps/Util.h
index fc6ac8622d..36cd505f4e 100644
--- a/source/ps/Util.h
+++ b/source/ps/Util.h
@@ -1,4 +1,4 @@
-/* Copyright (C) 2023 Wildfire Games.
+/* Copyright (C) 2025 Wildfire Games.
  * This file is part of 0 A.D.
  *
  * 0 A.D. is free software: you can redistribute it and/or modify
@@ -21,8 +21,12 @@
 #include "lib/file/vfs/vfs_path.h"
 #include "lib/os_path.h"
 #include "lib/status.h"
+#include "lib/types.h"
 #include "ps/CStr.h"
 
+#include <cstddef>
+#include <string>
+
 class Tex;
 
 const wchar_t* ErrorString(int err);
diff --git a/source/ps/VideoMode.cpp b/source/ps/VideoMode.cpp
index 629cdc7ef2..0d082db537 100644
--- a/source/ps/VideoMode.cpp
+++ b/source/ps/VideoMode.cpp
@@ -27,7 +27,7 @@
 #include "lib/config2.h"
 #include "lib/debug.h"
 #include "lib/file/vfs/vfs.h"
-#include "lib/file/vfs/vfs_path.h"
+#include "lib/path.h"
 #include "lib/status.h"
 #include "lib/sysdep/os.h"
 #include "lib/tex/tex.h"
@@ -45,6 +45,7 @@
 #include "renderer/backend/dummy/DeviceForward.h"
 #include "renderer/backend/gl/DeviceForward.h"
 #include "renderer/backend/vulkan/DeviceForward.h"
+#include "scriptinterface/ScriptInterface.h"
 
 #include <SDL.h>
 #include <SDL_error.h>
diff --git a/source/ps/VideoMode.h b/source/ps/VideoMode.h
index 80bb54c253..d33407a038 100644
--- a/source/ps/VideoMode.h
+++ b/source/ps/VideoMode.h
@@ -18,21 +18,14 @@
 #ifndef INCLUDED_VIDEOMODE
 #define INCLUDED_VIDEOMODE
 
-#include "graphics/Camera.h"
-#include "ps/CStrForward.h"
 #include "renderer/backend/Backend.h"
 
 #include <memory>
 
-typedef struct SDL_Window SDL_Window;
+class CStrW;
+namespace Renderer::Backend { class IDevice; }
 
-namespace Renderer
-{
-namespace Backend
-{
-class IDevice;
-}
-}
+typedef struct SDL_Window SDL_Window;
 
 class CVideoMode
 {
diff --git a/source/ps/VisualReplay.cpp b/source/ps/VisualReplay.cpp
index 81fecc6e5e..1c19411f88 100644
--- a/source/ps/VisualReplay.cpp
+++ b/source/ps/VisualReplay.cpp
@@ -30,6 +30,7 @@
 #include "network/NetClient.h"
 #include "network/NetServer.h"
 #include "ps/CLogger.h"
+#include "ps/CStr.h"
 #include "ps/Game.h"
 #include "ps/GameSetup/CmdLineArgs.h"
 #include "ps/GameSetup/Paths.h"
@@ -46,6 +47,7 @@
 #include <js/Array.h>
 #include <js/PropertyAndElement.h>
 #include <js/RootingAPI.h>
+#include <js/Value.h>
 #include <map>
 #include <string>
 #include <tuple>
diff --git a/source/ps/VisualReplay.h b/source/ps/VisualReplay.h
index 6aa848b6cd..de3763158d 100644
--- a/source/ps/VisualReplay.h
+++ b/source/ps/VisualReplay.h
@@ -1,4 +1,4 @@
-/* Copyright (C) 2021 Wildfire Games.
+/* Copyright (C) 2025 Wildfire Games.
  * This file is part of 0 A.D.
  *
  * 0 A.D. is free software: you can redistribute it and/or modify
@@ -19,10 +19,13 @@
 #define INCLUDED_VISUAL_REPLAY
 
 #include "lib/os_path.h"
-#include "ps/CStrForward.h"
 #include "scriptinterface/ScriptTypes.h"
 
+#include <js/TypeDecls.h>
+
+class CStrW;
 class ScriptInterface;
+namespace JS { class Value; }
 
 /**
  * Contains functions for visually replaying past games.
diff --git a/source/ps/World.h b/source/ps/World.h
index eadfc5d44e..7c4f45d539 100644
--- a/source/ps/World.h
+++ b/source/ps/World.h
@@ -24,15 +24,18 @@
 #ifndef INCLUDED_WORLD
 #define INCLUDED_WORLD
 
-#include "ps/CStrForward.h"
 #include "ps/Errors.h"
 
-#include <js/PropertyAndElement.h>
-#include <js/RootingAPI.h>
 #include <js/TypeDecls.h>
-#include <js/Value.h>
 #include <memory>
 
+class CGame;
+class CMapReader;
+class CStrW;
+class CTerrain;
+class CUnitManager;
+class ScriptContext;
+
 #ifndef ERROR_GROUP_GAME_DEFINED
 #define ERROR_GROUP_GAME_DEFINED
 ERROR_GROUP(Game);
@@ -40,12 +43,6 @@ ERROR_GROUP(Game);
 ERROR_SUBGROUP(Game, World);
 ERROR_TYPE(Game_World, MapLoadFailed);
 
-class CGame;
-class CUnitManager;
-class CTerrain;
-class CMapReader;
-class ScriptContext;
-
 /**
  * CWorld is a general data class containing whatever is needed to accurately represent the world.
  * This includes the map, entities, influence maps, tiles, heightmap, etc.
diff --git a/source/ps/algorithm.h b/source/ps/algorithm.h
index 2e4e28fdbd..c2a5709ef7 100644
--- a/source/ps/algorithm.h
+++ b/source/ps/algorithm.h
@@ -19,6 +19,7 @@
 #define ALGORITHM_H
 
 #include <algorithm>
+#include <cstddef>
 #include <string>
 #include <string_view>
 
diff --git a/source/ps/scripting/JSInterface_SavedGame.cpp b/source/ps/scripting/JSInterface_SavedGame.cpp
index 7887b5dd83..ac3b1bc53c 100644
--- a/source/ps/scripting/JSInterface_SavedGame.cpp
+++ b/source/ps/scripting/JSInterface_SavedGame.cpp
@@ -23,6 +23,7 @@
 #include "network/NetClient.h"
 #include "network/NetServer.h"
 #include "ps/CLogger.h"
+#include "ps/CStr.h"
 #include "ps/Game.h"
 #include "ps/SavedGame.h"
 #include "scriptinterface/FunctionWrapper.h"
diff --git a/source/ps/scripting/JSInterface_VFS.h b/source/ps/scripting/JSInterface_VFS.h
index f9f93794d0..719e77aea8 100644
--- a/source/ps/scripting/JSInterface_VFS.h
+++ b/source/ps/scripting/JSInterface_VFS.h
@@ -21,6 +21,8 @@
 #include "lib/types.h"
 #include "scriptinterface/ScriptTypes.h"
 
+#include <js/PropertyDescriptor.h>
+
 class ScriptRequest;
 
 namespace JSI_VFS
diff --git a/source/ps/tests/test_Future.h b/source/ps/tests/test_Future.h
index c54e2a93fd..4cc8c29360 100644
--- a/source/ps/tests/test_Future.h
+++ b/source/ps/tests/test_Future.h
@@ -22,7 +22,6 @@
 #include <cstring>
 #include <exception>
 #include <functional>
-#include <memory>
 #include <new>
 #include <type_traits>
 #include <utility>
diff --git a/source/scriptinterface/ScriptInterface.cpp b/source/scriptinterface/ScriptInterface.cpp
index 6c5d2ab4c7..2fda1ed7ce 100644
--- a/source/scriptinterface/ScriptInterface.cpp
+++ b/source/scriptinterface/ScriptInterface.cpp
@@ -20,6 +20,7 @@
 #include "ScriptInterface.h"
 
 #include "lib/debug.h"
+#include "lib/file/vfs/vfs_util.h"
 #include "lib/utf8.h"
 #include "ps/CLogger.h"
 #include "ps/Filesystem.h"
diff --git a/source/simulation2/components/tests/test_scripts.h b/source/simulation2/components/tests/test_scripts.h
index 2a0a523a3e..5e19aa23bc 100644
--- a/source/simulation2/components/tests/test_scripts.h
+++ b/source/simulation2/components/tests/test_scripts.h
@@ -1,4 +1,4 @@
-/* Copyright (C) 2024 Wildfire Games.
+/* Copyright (C) 2025 Wildfire Games.
  * This file is part of 0 A.D.
  *
  * 0 A.D. is free software: you can redistribute it and/or modify
@@ -15,6 +15,7 @@
  * along with 0 A.D.  If not, see <http://www.gnu.org/licenses/>.
  */
 
+#include "lib/file/vfs/vfs_util.h"
 #include "simulation2/system/ComponentTest.h"
 #include "simulation2/serialization/StdDeserializer.h"
 #include "simulation2/serialization/StdSerializer.h"
diff --git a/source/simulation2/system/CmpPtr.h b/source/simulation2/system/CmpPtr.h
index b77cc02262..648929e1ad 100644
--- a/source/simulation2/system/CmpPtr.h
+++ b/source/simulation2/system/CmpPtr.h
@@ -1,4 +1,4 @@
-/* Copyright (C) 2015 Wildfire Games.
+/* Copyright (C) 2025 Wildfire Games.
  * This file is part of 0 A.D.
  *
  * 0 A.D. is free software: you can redistribute it and/or modify
@@ -20,6 +20,8 @@
 
 #include "simulation2/system/Entity.h"
 
+#include <cstddef>
+
 class CSimContext;
 class CSimulation2;
 class IComponent;
diff --git a/source/simulation2/system/Entity.h b/source/simulation2/system/Entity.h
index 6c493e8d9b..4f7088c594 100644
--- a/source/simulation2/system/Entity.h
+++ b/source/simulation2/system/Entity.h
@@ -1,4 +1,4 @@
-/* Copyright (C) 2017 Wildfire Games.
+/* Copyright (C) 2025 Wildfire Games.
  * This file is part of 0 A.D.
  *
  * 0 A.D. is free software: you can redistribute it and/or modify
@@ -20,6 +20,8 @@
 
 #include "lib/types.h"
 
+#include <cstddef>
+
 class IComponent;
 
 /**
diff --git a/source/tools/atlas/GameInterface/Handlers/MapHandlers.cpp b/source/tools/atlas/GameInterface/Handlers/MapHandlers.cpp
index 0a4618ffbe..e325fd1aed 100644
--- a/source/tools/atlas/GameInterface/Handlers/MapHandlers.cpp
+++ b/source/tools/atlas/GameInterface/Handlers/MapHandlers.cpp
@@ -33,6 +33,7 @@
 #include "graphics/TerrainTextureManager.h"
 #include "lib/bits.h"
 #include "lib/file/vfs/vfs_path.h"
+#include "lib/file/vfs/vfs_util.h"
 #include "lib/status.h"
 #include "maths/MathUtil.h"
 #include "ps/CLogger.h"