[Iseweasel](https://en.wikipedia.org/wiki/Mozilla_Corporation_software_rebranded_by_the_Debian_project#IceWeasel) is a fork of Firefox which was made by the Debian project because the license conditions of the Firefox name and logo violate the Debian Free Software Guidelines.

What does Debian need to change in Firefox to make Iceweasel compliant with the DFSG?