I appreciate that these will scale better than images, but I never grokked the icons in the top right corner. To me, a repository isn't much like a "book", and I still remember hunting for the "log out" link in frustration before realizing it was the door with an arrow. Since you've pretty much pegged the header at ~900px wide, I still think text links would be more usable and you have the horizontal room for it.

That being said, since it seems like you're incorporating these metaphors into other parts of the site--like I notice the book icon by the repo name now--maybe the metaphors will eventually stick. But in the meanwhile it has been a little confusing.