The Fedora project has recently revamped its default startpage for Firefox ( http://start.fedoraproject.org/ )
This is how it used to look:
and this is how it looks now:
This is a massive improvement over the old style. Good work Fedora Project.
I recently moved my Linksys WAG54GS router from plain http to https access for its maintenance page. Even though I only have it accessible internally I like to be as secure as possible and given this was an easy fix I just did it.
Today I got these errors in Firefox 3.0.8:


So, I assumed that the certificate had became broken or changed in some way. So I delved into the Certificates area of my Firefox (Edit -> Preferences -> Advanced -> Encryption -> View Certificates) and I deleted the one for my router, easy to spot as it had its IP address listed.

I tried again, nothing, same error. I closed and reopened Firefox. Same error.
The solution for this one in particular is that there is also a Security Device certificate installed in the Authorities section listed as Cisco Linksys. Once I deleted this one it then gave me the normal screen as if I’d never connected to my router before.

The recommendation from Mozilla regarding this is here *Mozilla*