install icecat on debian 9 64bit main

https://ftp.gnu.org/gnu/gnuzilla/60.3.0/icecat-60.3.0-gnu1.tar.bz2 is the source code. https://ftp.gnu.org/gnu/gnuzilla/60.3.0/icecat-60.3.0.en-US.gnulinux-x86_64.tar.bz2 is the version compiled for x86-64 (execute the icecat file).

https://invidio.us/watch?v=TC5Xv0F-Zyw proposes to add Trisquel's repository. I would not do that although I understand while it probably does not raise troubles (Debian 9's packages are at least as recent as Trisquel 8's).

Don't just go and add foreign repositories to your system. There is a reason why all distributions use their own repository. It will only create problems later on if you do so. The "I have to reinstall the whole system to fix it" kind of problems. Not necessarily, but possible.

You can download the binary package built for 32-bit or 64-bit GNU/Linux (Magic Banana's second link is the 64-bit version).

Once you download that, extract the archive in your home directory. Then you can already start the application from there. You can also edit the application menu and add a starter for IceCat, or add a starter somewhere else, like desktop etc.

It does leave you without updates for the browser though.

If you want to have updates, you can use this: BrunoAlexandreMiguel GNU IceCat PPA.

Follow the instructions there, and you'll be able to have an apt-managed installation of IceCat.