Discovered with the new Web Inspector XSLT logging: parsing errors were attributed to a wrong file. Fixing this made an existing test fail, but the test was incorrect (the new behavior matches xsltproc and WinIE).
Created attachment 16945 [details]
...as for Firefox, it passes neither variant - AFAICT, it doesn't try to load the DTD.
Created attachment 16946 [details]
Oops, there was one more test with the same problem.
Comment on attachment 16946 [details]
Does href() return the absolute URL?
(In reply to comment #3)
> Does href() return the absolute URL?
It did in my tests, and I think it's always supposed to.
Committed revision 27302.