<xi:include href="ARB_vertex_type_2_10_10_10_rev.xml" xmlns:xi="http://www.w3.org/2001/XInclude"/>
-<!-- ARB extensions #86...#90 -->
+<!-- ARB extensions #86...#89 -->
+
+<xi:include href="ARB_shader_subroutine.xml" xmlns:xi="http://www.w3.org/2001/XInclude"/>
<xi:include href="ARB_tessellation_shader.xml" xmlns:xi="http://www.w3.org/2001/XInclude"/>