Over this day I have added mod_pagespeed including some fine tuning for Magento. After enabling it (lastest stable x86_84 for Fedora 17 / CentOS) I got a lot xml errors.
However I was able to fix all of these errors.
The convert_meta_tags filter of mod_pagespeed has changed the whole initial site definition to xml even it is still html because of this meta, added in past for the semantic web extension:
<html xmlns=”http://www.w3.org/1999/xhtml” version=”XHTML+RDFa 1.0″ xml:lang=”en”>
Here are my settings for /etc/httpd/conf.d/pagespeed.conf:
# endur 14-10-12
# endur 14-10-12 – enhanced cache for images
Really important was the disabled convert_meta_tags filter to get mod_pagespeed working for me. The result is really impressive!