apt-get update returns error 404 because of iceweasel

Question

Since Debian uses firefox instead of iceweasel, apt-get update returns 404 errors with this URL:

http://mozilla.debian.net/dists/wheezy-backports/iceweasel-release/binary-amd64/Packages

I had installed firefox-esr in order to migrate to firefox and I have no problem, I can use Firefox.

I use rvm and when I try to install ruby with it, it stop the installation because apt-get update returns a error 404. Read this.

I use Kali Linux and my sources.list is clean:

#kali 2.0
deb http://http.kali.org/kali sana main non-free contrib
deb http://security.kali.org/kali-security/ sana/updates main contrib non-free

How to delete these 404 errors?

Answer 1

Find and remove line saying:

deb http://mozilla.debian.net/...

If it is not in /etc/apt/sources.list, then it is somewhere else, most probably /etc/apt/sources.list.d/*.

You can also use fgrep -r mozilla.debian.net /etc to find it.

Note that this file might be part of some old debian package (find out which with dpkg -S /etc/apt/sources.list.d/blahblah.conf) - in that case, it is probably best to dpkg --purge that old iceweasel package.