Index: openacs-4/packages/acs-templating/tcl/head-procs.tcl
===================================================================
RCS file: /usr/local/cvsroot/openacs-4/packages/acs-templating/tcl/head-procs.tcl,v
diff -u -N -r1.28 -r1.29
--- openacs-4/packages/acs-templating/tcl/head-procs.tcl	24 Mar 2018 16:15:39 -0000	1.28
+++ openacs-4/packages/acs-templating/tcl/head-procs.tcl	10 Apr 2018 07:09:31 -0000	1.29
@@ -37,6 +37,10 @@
     for e.g updating references to external resources when switching
     between a CDN and a local resource, or when a resource should be
     updated.
+
+    We could consider a dns-prefetch for CDN requests. When the
+    url-check is performed at register time, the performance for
+    processing the url can be neglected.
     
 } {
     set ::template::head::urn($urn) $resource