The Firefox/Iceweasel issue came about due to Mozilla's trademark policy conflicting with Debian's stable release policy. Mozilla would not allow Debian to create their own stable version of Firefox by backporting patches while still calling it Firefox.Mozilla has this degree of control due to trademark law. The code is free and open source, but the trademark belongs to Mozilla.
Debian's policy is no version updates to stable releases, just security and bug fixes. Mozilla's policy was that distributors were not to create their own LTS version of the browser while still using the Firefox trademark.
Mozilla now has their own official LTS version, which is what Debian packages in their stable distro. Since the impasse has been resolved, Firefox is now Firefox again in Debian.