It has to do with how [https://trisquel.info/en/wiki/how-trisquel-made
Trisquel is made]. Trisquel is made from Ubuntu and Ubuntu has 4 repository
components
1) Main - Officially supported software.
2) Restricted - Supported software that is not available under a completely
free license.
3) Universe - Community maintained software, i.e. not officially supported
software.
4) Multiverse - Software that is not free.
That package [in ubuntu 11.10] which is the basic equivalent if Trisquel 5.5
has that package in the multiverse repository. I don't know why it is there
(it appears to be GPL) but maybe there is some patent restriction or
something. We don't import any packages from the multiverse repo because for
whatever reason they are determined by the Ubuntu community to be non-free.
Hope that answers your question.