Why is there a separate bitcoin and bitcoin-core GitHub repo? – Beragampengetahuan

Can someone explain why these two repositories exist at the same time?

-core

It is a bit confusing for a newcomer to the codebase what to actually trust.
Furthermore, is there some good intro somewhere that explains how access to this repository is managed? Like who can become eligible to approve merge requests and for what reasons could this right be stripped from a person again.

Thanks a lot!