We have an httpbb test that verifies appservers do the right thing with article titles that happen to end with .z, based on T75274 way back in 2014 when an Apache config bug was triggered by https://fr.wikipedia.org/wiki/K.A.Z . That test started failing sometime recently (Content-Encoding header: expected 'gzip', was missing) and I haven't been able to pin down what changed or whether it was expected.

I'm disabling the test, to restore everything to a passing state in production, but leaving this open to investigate. If the behavior wasn't supposed to change, we'll restore it and re-enable the test; otherwise we'll update the test, or if it's completely obsolete, just leave it disabled and close this.