It's definitely ok to not know what flutter is. It seems a little unreasonable to expect specialized projects to define everything from the ground up, though.

100% agree. Haven’t been trying to suggest otherwise. Firmly in the camp that mentioning Flutter is more than enough, and discovering what it is should be left as an exercise for the reader. This all started because I was mildly disputing that this was only of interest to someone already interested in Flutter itself, as opposed to the problem space.