Hello. While at one time org XHTML output validated successfully, now the
default values of certain variables in ox-html cause the resulting output
to not validate as XHTML 1.0 Strict.

org-html-infojs-template: script tag attribute "type" is required (2x)
org-html-style-default: style tag attribute "type" is required

Also the following output gives the error "there is no attribute 'role'".


<div id="table-of-contents" role=*"*doc-toc">


The same for this output:

role=*"*doc-backlink"