[GFSD] fonts-ubuntu* requires proprietary software to be built from source + probable licensing issue

Joerg Jaspert explains both problems in https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=603157#30

His last paragraph deals with the need for proprietary tools to build the fonts from source (which is *not* the .ttf files). As far as I understand (and jxself expressed the same understanding), it is enough to kick the fonts-ubuntu* packages out of Trisquel's repository.

The problem with https://ubuntu.com/legal/font-licence (explained before, in Joerg Jaspert's message, and in https://bugs.launchpad.net/ubuntu-font-licence/+bug/1167425 too, by Ejectmail) is quite technical. Here is my short summary, copied from https://trisquel.info/fr/forum/package-non-free-trisquel-9 where the issue was raised:

As far as I understand, the fundamental problem is the point 2.3 of the license. It would impose my hypothetical "modified version which is not substantially changed" of "Ubuntu font" to be named, e.g., "Ubuntu font derivative Magic", to both retain the original name and to distinguish these derivative fonts from the original. According to Ejectmail on bugs.launchpad.net, a trademark policy could then additionally prohibits the use of the original name, thus creating a conflict with the license that effectively prohibits changes that are not "substantial". Also, on Debian's mailing list, Joerg Jaspert notes that the definition, in the license, of "Substantially Changed" is unclear. Since modified versions with "substantial changes" must not use the original name, it is a problem as well.

Quoting that summary, chaosmonk wrote: "This is my understanding as well".

The bug affects all versions of Trisquel.