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 # OpenCL-Registry
-OpenCL API and Extension Registry.
+
+This repository contains the OpenCL API and Extension Registry. It is also
+used as a backing store for the web view of the registry at
+https://www.khronos.org/registry/cl/ ; commits to the master branch of this
+repository will be reflected there.
+
+In the past, the OpenCL registry was maintained in a public Subversion
+repository. The history in that repository has not been imported to github,
+but it is still available at
+https://cvs.khronos.org/svn/repos/registry/trunk/public/cl/ .
+
+Interesting files in this repository include:
+
+* index.php - toplevel index page for the web view. This relies on PHP
+  include files found elsewhere on www.khronos.org and so is not very useful
+  in isolation.
+* cl.xml - enumerant and extension number registry. Documents the assigned
+  OpenCL enumerant ranges, and the names and index numbers assigned to
+  OpenCL extension specifications.
+* extensions/ - OpenCL extension specifications, grouped into
+  vendor-specific subdirectories.
+* sdk/ - OpenCL reference pages and reference cards. There are separate sets
+  for each API version.
+* specs - OpenCL specification documents.