The big red flag should be giving github access before signing any contracts.

Yeah at least when you interview locally in your areas, you get to meet them before you get a random test assignment.

But also online, once or twice I received these Leetcode style sites to register and do a few tests before we meet, which was weird for me and I just ignored it.

One of them later asked "Why I didn't have time to do it yet" and I told them I first meet people and check the fit before I do tests, like who the hell does that differently?

Hope it hasn't become a way more common thing.

They mostly use public repositories though.

Yeah, but that should also be a red flag.