Font locking of LaTeX constructs for specifying verbatim
content is done with syntactic keywords in AUCTeX. There are
two features in GNU Emacs which AUCTeX relies upon and which
are not present in XEmacs:
Attached is a sync of font-lock with FSF 21.2 that I did awhile ago. I am
not 100% that this works but I think it did at one point. Maybe this
contains what you want.