The Khronos OpenCL ICD Loader is a system library that provides the OpenCL Installable Client Driver (ICD) discovery and dispatch mechanism. It exports the standard OpenCL API symbols (e.g., clGetPlatformIDs, clCreateContext) that applications link against. On Linux, it scans /etc/OpenCL/vendors for .icd files; on Windows, it queries the registry under HKLM\SOFTWARE\Khronos\OpenCL\Vendors and also supports DXGI adapters and AppPackage enumeration. It builds a dispatch table for each ICD and forwards API calls to the appropriate driver based on object handle dispatch pointers. The loader also supports an experimental layer mechanism that chains optional interceptor libraries. An optional command-line tool, cllayerinfo, lists available layers. The codebase is structured with platform-specific modules for library loading, environment variable parsing (with secure variants), and tracing (controlled by OCL_ICD_ENABLE_TRACE). A large portion of the dispatch code is generated via Mako templates from the official OpenCL XML registry, ensuring API completeness. The test suite uses a driver stub to validate correct dispatching across all OpenCL entry points.