Original sentence: By December 2008, Trisquel was included by the FSF in its list of Linux distributions endorsed by the Free Software Foundation.Trisquel (officially known as Trisquel GNU/Linux) is a Linux operating system based on the Ubuntu Linux distribution
Edited sentence: By December 2008, Trisquel was included by the FSF in its list of GNU/Linux distributions endorsed by the Free Software Foundation.Trisquel (officially known as Trisquel GNU/Linux) is a GNU/Linux operating system based on the Ubuntu GNU/Linux distribution