About time. It's absolutely ridiculous that this hasn't existed for the past 10 years.
We've had the ability to temporarily disable PR's for a while for maintainers but we felt like it was time to look at this again and see what folks think.
Collaboration on repos where the authors explicitly don't accept PRs and are going to auto close or ignore them? I don't get it - it's not like you're going to force opensource on anyone.
Also I don't find GitLab that much better. I remember the feature request for "Give option to disable automatic adding of 'Closes ISSUE' to merge requests" closed with "Why would you need an option for that, everyone either loves it or likes manually removing it every time.