Permissions. I specifically remember talking to Tom and Chris about how that was really the main point of rage that spawned the idea of GitHub (and its original slogan “Git hosting: No longer a pain in the ass”).
If you averaged the time out, it may not have hit the five hour per week mark, but it combined with other time savers (linking Git directly with the issue tracker for example instead of having to figure out how to cross reference them) easily did/does.
The claim was 5 hours per employee per week. I found that it took far less than 50 hours a week when working at a 10 person company. And if it did, I'd question the competence of whoever was doing that maintenance.
I'd pin it at closer to 3 or 4 minutes per employee per week, with maybe 8 hours of setup once. That's still a bunch of work, but it's a whole different ballgame.