Last year I have manually added Mate repos to install Mate, added Debian experimental and unstable to install iceweasel 19, and to solve a vlc player dependecy problem. Today I realised, that all manual changes were gone from every file in sources.list.d.

# apt-show-versions -a -p iceweasel
iceweasel 19.0~b3-1 install ok installed
No stable version
iceweasel 10.0.12esr-1 testing ftp.hu.debian.org
iceweasel 19.0~b3-1 newer than version in archive
root@Mantix:/home/enzo

I have played with smxi (adding liquorix kernel repo) and did an apt-get upgrade.

Any idea what happened?

Probably desktop defaults got upgraded and it reverted the sources.list back.

Are you using dev in the antiX repo?

I only changed debian repos, and added Mate, opera, skype, iceweasel-beta. I was tracking the testing release, except iceweasel and vlc.