Indeed, there is a severe problem. Evidence, methinks, that we should have done this in a branch. Sigh. Anyway, I have ascertained that the problem is caused by the removal of the teix:egXML template from html/html_tagdocs.xsl.
So obviously we could just put it back, that solves the problem.
But it is not a good solution, IMHO, to have two of the exact same template in two seaprate files. I am going to suggest it is worth some time to figure out an alternate solution. (If we cannot find a solution, or just get fed up before we do, we can always
put it back, and go on with successful Stylesheets and our tail between our legs. :-)
Stylesheets builds are broken too, but that'll just be tests. :-)
No time to look at anything today, unfortunately.