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+# Extra CMake Modules `extra-cmake-modules/`
+
+> **Type**: CMake Module Collection  
+> **License**: BSD-3-Clause  
+> **Fork Origin**: [KDE ECM](https://api.kde.org/ecm/)
+> **Status**: Detached Fork (independently maintained)
+> **Latest Version**: 0.0.5-1
+
+---
+
+## Overview
+
+Extra CMake Modules (ECM) provides additional CMake modules beyond what CMake ships by default. This includes:
+
+- `find_package()` modules for common software
+- Utility modules for common CMake tasks
+- Toolchain files for cross-compilation
+- Common build settings used by KDE software
+
+While ECM originates from the KDE project, it is useful for any CMake-based project.
+
+---
+
+## Usage in ProjT Launcher
+
+ECM is used for:
+
+- **Qt integration** - Finding Qt components
+- **Build utilities** - Common CMake patterns
+- **Cross-platform support** - Toolchain configurations
+
+---
+
+## Key Modules
+
+| Module | Purpose |
+|--------|---------|
+| `ECMQueryQt` | Query Qt installation details |
+| `ECMInstallIcons` | Install icon themes |
+| `ECMGenerateHeaders` | Generate forwarding headers |
+| `ECMSetupVersion` | Configure project versioning |
+
+---
+
+## Build Integration
+
+ECM is included as a subdirectory:
+
+```cmake
+add_subdirectory(extra-cmake-modules)
+list(APPEND CMAKE_MODULE_PATH "${CMAKE_SOURCE_DIR}/extra-cmake-modules/modules")
+```
+
+---
+
+## Documentation
+
+- [ECM API Documentation](https://api.kde.org/ecm/)
+- [KDE Community Wiki](https://community.kde.org/Policies/CMake_Coding_Style)
+- [Original README](../../extra-cmake-modules/README.md) — Upstream library documentation
+
+---
+
+## Related Documentation
+
+- [Third-party Libraries](./third-party.md)
+- [Workflows](./workflows.md)