F9: What's up with the Firefox home page?

[Joe Smith]

F9, firefox-3.0-0.60.beta5.fc9.i386

When I start firefox, it opens this page:
http://start.fedoraproject.org/

The preferences say "When Firefox starts, show my homepage", so one 
might reasonably infer that start.fedoraproject.org is the default home 
page for Fedora-packaged firefox.

However, if I click the "home" button on the toolbar, or use Alt+Home, I 
get the Google Firefox home page:
http://www.google.com/firefox?client=firefox-a&rls=org.mozilla:en-US:official

Even explicitly setting my home page back to start.fedoraproject.org 
does not change the behavior of the home button.

I could swear that the home button used to simply take me to the Fedora 
start page, but not now.

I know it's stupid thing; I don't much care which page is used, but I'd 
very much like to know what's going on. Maybe something to do with FF3 
entering release-candidate phase?

<Joe