I'm running Ubuntu 11.10, and, for web development, need to install Firefox 5 specifically. I know I can do it by hand from the Mozilla download. But I'd like a Ubuntu package. Is one available? How do I do this?
You can still get the firefox 5 deb from the Ubuntu Mozilla Security Team PPA for Ubuntu 11.04 (should also work under 11.10). Beware, it will replace your current firefox package. You would need to find a specific firefox-5 package.
You may also be interested in cross browser testing.