The validator says:
"This document uses an inconsistent DOCTYPE declaration. The System Identifier http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd declares the XHTML 1.0 Transitional document type, but the associated Public Identifier -//W3C//DTD Xhtml 1.0 Transitional//EN does not match this document type.
The recommended Public Identifier for http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd is -//W3C//DTD XHTML 1.0 Transitional//EN."
Did we change the DOCTYPE ... is this on every page owen?
Created attachment 3921 [details] [review]
In the transition to Template::Toolkit a part of the DOCTYPE got its case switched, making it invalid: XHTML was changed to Xhtml.
Correcting the case in the two include files (one for OPAC, one for staff client) quiets errors in the validator.
Pushing this patch, please test