Whoever wrote the FAQ did a great job:
I notice this website refers to Trisquel as a distribution of "GNU/Linux"
and not "Linux". Why?
There is a long-standing naming controversy. Most people who use the system
today don't know that what they're actually using is the GNU system combined
with the kernel Linux. For many years, the media and the user community
itself has given undue weight to the contributions that come from Linus
Torvalds' camp and fostered a skewed account of the operating system's
history, while barely acknowledging the existence of the GNU project at all.
The GNU project was started in 1984 by Richard Stallman to develop a complete
free operating system, because none existed at the time. Its design closely
followed that of Unix because Unix was highly machine-portable and (at that
time) pervasive. Linus Torvalds did not write a whole operating system, he
only wrote the last missing piece, a kernel, and he only did that in the
first place because development of Hurd, the GNU project's own kernel, was
lagging behind (and has not been completed to this day). Torvalds didn't
write the kernel because of a belief in "open source", a term that wasn't
even coined until 1998 and misses the point of free software, and he
originally released it in 1991 under a proprietary license until he was
persuaded to relicense it under the GPL the next year. Saying "GNU/Linux"
instead of "Linux" is fairer and more accurate. Without the irreplaceable
software contributed by the GNU project − and even more importantly, the
founding ideas of freedom − the system most mistakenly call "Linux" would
not exist. It's that simple.
https://trisquel.info/en/faq
