oh yeeah, you're right, I accidentally wrote { contentlinks => 'repo' } in my above reply but of course i wouldn't make sense to link back to "repo". join => { contentlinks => 'content' } is the correct path.

I'm also never sure whether prefetch alone is sufficient. For the cases I had so far, it seems to be but then the docs always seem to include both so I do it as well to be on the safe side just in case this behaviour is changed in future version.