It hosted repos, and broke links to those repos and links within them. It also broke processes that relied on the repo, e.g. automatic issue creation in CI, but that's less serious.
Setting up a redirect works if you are the administrator of the project...and are still alive. Migrating a project was simple if it didn't have a wiki. There are a lot of details that caused some real headaches. I remember it being like a mini Y2k at the time, and there's no telling how much we just collectively lost from it.
URLs that change without good reason are a PITA.