So, my apologies for being picky, but… I set my system to English (Canada) but I’m still seeing colour misspelled as color. It would be nice if I was seeing Canadian English spellings when the system is set to do so. Thank you.
The translations for that application are handled by gnome.
Here is how you would get involved there if you wanted to help:
Here is an open translation issue from 9 months ago that describes your same issue:
Is there a specific application that has the wrong spelling?
From the screenshot above, at the very least gnome settings has the wrong spelling.