I visit a web site which supports Basic, Negotiate and NTLM auth.: With Firefox 30 I could authenticate by Negotiate or NTLM, I don't think it would ever try Basic. Certainly I never saw a password prompt, because Negotiate and NTLM authentication are all handled automatically (the latter with Samba's ntlm_auth helper). Firefox 31 (firefox-31.0-1.fc20.x86_64) appears to be trying Basic auth before NTLM or even Negotiate. I get a password prompt; if I fill it in then I can see it trying Basic auth; if I hit cancel then it goes ahead and tries Negotiate like it should have done in the first place, which works. This is broken; please don't ship this as an update in Fedora 20 until it's fixed.
Apologies, this isn't a regression. It's just that the server randomises the order of its WWW-Authenticate: headers and it *happened* to give me Basic first when I was testing Firefox 31, and not when I was testing Firefox 30. If I keep hitting 'reload', I see the same bug with Firefox 30 when the server sends Basic first. So it's still a bug, but not a regresion.
Thanks, let's track it upstream - https://bugzilla.mozilla.org/show_bug.cgi?id=650091