In virtual shell, "Trisquel" is wrongly shown as my OS

Somehow -- I think as an artifact or by-product of my having installed the GNU IceCat web browser -- whenever I drop into the virtual shell, using the Ctrl-Alt-F1 command, what I see displayed at the top of the black screen is:

Trisquel GNU/Linux 6.0.1 jbox tty1

However, I am not running or using Trisquel in any way as far as I'm aware of, and I've deleted everything I could find with that name. What it should say is:

Ubuntu 16.04 LTS jbox tty1

(or, maybe, "Ubuntu Mate 16.04 LTS jbox tty1").

Would anyone know:

(a) How it got there, but more importantly,

(b) How I should I get rid of it and replace it with the correct name of the OS I'm actually running?

I'd also like to just make sure there's nothing else going on with Trisquel (& that there are no other consequences, functions or appearances of it) in my system.

(I think I've deleted everything, or almost everything, having to do with it.) Thanks!