"By enabling more and more third-party sources, what does your
sources.list look like? I think it become hard to read and manage,
right? OK, with Ubuntu Tweak 0.4.9, you will have a more manageable
way with Third Party Sources. By default, Ubuntu Tweak will save
the third party sources into its own file under
/etc/apt/sources.list.d/. When you open the Source Editor, Ubuntu
Tweak will show you the main sources.list in the window.
"First, a lot of PPA has been added, they are: aMule, Google
Testing Repository, GmChess (Chinese Chess), Smplayer Testing, GIMP
Testing, Back In Time (Backup tool), Geany, SpiceBird, Moblin
Testing, PlayOnLinux, RedNotebook, Breathe Icon Theme, Qt, Mono,
Exaile, Clutter, Ubuntu X Unstable, Gloobus……"