I typed "Lliw baner Cymru ydy coch, gwyn a gwyrdd" but it said it should be "Lliw baner Cymry ydy coch, gwyn a gwyrdd," why is this? I've never seen "Cymry" before
It certainly shouldn't have said that. Cymru is the name for the country, whereas "Cymry" means "Welsh" (as in the people "Y Cymry"="The Welsh).
Ah, diolch! I'm guessing it's just a typo, so I'll report it if it comes up again.