What steps will reproduce the problem?
1. Allow linux users who use the "iceweasel" version of firefox to install
the code.

What is the expected output? What do you see instead?
It should recognize iceweasel as a valid version of firefox.

What version of the product are you using? On what operating system?
The most recent version of iceweasel on linux debian testing.

Please provide any additional information below.
It is absolutely absurd that no one has taken care of this!  People have
been asking for two years!  How hard can this be!

At the very least, you should not LIE and say that you can install gears on
Linux, when you CANNOT BECAUSE NO ONE PAYS ATTENTION TO THE BUG REPORTS!