I've just tested this with the 11.10 beta 2 64bit LiveCD. Firefox recognised a .deb file as a Debian package and asked if I wanted to open it with the Ubuntu Software Center.
Package: firefox 7.0~b6+build1+nobinonly-0ubuntu1 Please update and test again. ** Changed in: firefox (Ubuntu) Status: Confirmed => Incomplete -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/830911 Title: Firefox by default doesn't know what to do with .deb files To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/firefox/+bug/830911/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs