Looks like it’s just random commenters taking random guesses because those have happened before.

What is a “repository reset”? One commenter writes:

There was a temporary similar “outage” back in July with rewritten history, apparently something inappropriate was recorded in the repo history they wanted cleaned out. The repo came back after that. I have no idea if this is the same thing, or if they just got tired of maintaining it.

Seems strange to me. You can prep locally and then force-push. I don’t see why rewriting history would require taking the repository down.