Non-free packages installed on duuni
tangerine-icon-theme Tangerine Icon theme
1 non-free packages, 0.0% of 2418 installed packages.
CC-BY-SA used in tangerine-icon-theme is actually free according to RMS/FSF, just not that endorsed. I do know myself that CC-BY and CC-BY-SA are free, but not everyone does - FSF doesn't directly endorse Creative Commons licenses since they have also so severely non-free licenses with the non-commercial and no-derivatives requirements, and it's very easy to mix the non-free licenses with free licenses.
Anyway, it's non-free only according to Debian, since they have concerns about CC-BY-SA anti-drm portions. For me, CC-BY-SA 3.0 is fine enough (tangerine is 2.5) and Free by all means. I also think the (not uniform) anti-drm position within Debian is a bit two-edged. Not allowing drm so that users are not restricted should be ok in the same sense it's not allowed to make free, copyleft (eg. GPL) code non-free. I don't think anti-drm sections are always good, or that's always needed for all software (not all software needs to be copyleft either, it's just means to get freely usable software for the users). But done in the right way it's good to take into account these all kinds of things that can be done to restrict free software's free usage, including drm/patents/etc. GPLv3 got it quite well done, even though not all parties - wanting restrictions - can use it.
See Definition of Free Cultural Works for more about licenses for content.
Additionally to that one package I usually tend to have mplayer, apparently not now. But it's also free software, and it probably should be reworked so that it's in universe in Ubuntu too, since it's in main in Debian nowadays. It was originally put to multiverse because of the patent problems and even possible non-free code, but since a) potential patent problems don't make a software non-free right away (everything is potentially problematic in the current software patents world - it means more if some patent is actively enforced) and b) Debian has worked on the problematic parts, it would be beneficial not to mark mplayer non-free anymore in Ubuntu.
I use OpenJDK for Java without any problems, and Gnash for Flash with a little more problems ;) but I just don't want that Adobe trash on my machine.