I've never looked at the code base and I could make a reasonable guess as to what it's about. I'm guessing it has to do with pasting a fediverse link into a post and making it point to the actual instance instead of the federated link.

I could be wrong but it looks like it would make sense to the maintainers of the code.

Or am I just missing a joke here?

Edit: sorry if this comes across dickish. I don't have context for the question. It looks frankly like a very efficient use of words — I'm a little bit in awe. Take away one word and it would be gibberish to me. My own commit messages are not nearly as efficient.