Merge branch 'master' into 280-group-warning
diff --git a/xml/gl.xml b/xml/gl.xml
index 00846ff..9422da3 100644
--- a/xml/gl.xml
+++ b/xml/gl.xml
@@ -79,7 +79,18 @@
         <type>typedef void (<apientry/> *<name>GLVULKANPROCNV</name>)(void);</type>
     </types>
 
-    <!-- SECTION: GL parameter class type definitions. -->
+    <!-- SECTION: GL parameter class type definitions.
+         The groups are intended to contain all the possible legal values
+         for corresponding function parameters, but it is likely that many
+         of the groups are out of date relative to current OpenGL and OpenGL
+         ES specifications, and the many extensions to those specifications.
+         As such, they may not be a reliable source for enumeration info.
+
+         We welcome assistance from the community in making the enum groups
+         more complete. Khronos does not use the enum group information,
+         and the OpenGL Working Group does not have internal resources to
+         bring it up to date.
+    -->
 
     <groups>
         <group name="EvalMapsModeNV">