Trisquel's software repository hosts following Fluendo mp3 decoder plugins:-
[1] gstreamer0.10-fluendo-mp3
[2] gstreamer1.0-fluendo-mp3
According to Fedora, although Fluendo plugin is free and open source
software, it is not freely redistributable because of its licensing terms[3].
Here is Fluendo's EULA (End User License Agreement), which I obtained from
their website[4].
[3] https://fedoraproject.org/wiki/Installing_the_Fluendo_MP3_plugin
[4] http://www.fluendo.com/static/documents/Fluendo-EULA-usa.pdf
Is it true that Fluendo EULA violate freedom to freely redistribute the
program?