Tips

How to change Background (wallpaper)

To set or change wallpaper,
Select Main Menu --> System --> Preferences --> Look & Feels --> Appearance --> Background
Or right-click on the empty area of Desktop --> Change Backgrounds

Difference between Linux-libre kernel and Debian kernel?
Refer to the following websites:

https://unix.stackexchange.com/questions/288027/what-are-the-differences-between-debian-linux-kernel-and-linux-libre
https://trisquel.info/en/forum/difference-between-linux-libre-kernel-and-debian-main-kernel
https://maruyuki.org/blog/2020/08/08/386/