How many requests does it require per user? When I built my license checker[0] I went with making requests straight from the browser to Github. It has a lower rate limit, but it's per-client, not tied to an API key.

[0] http://dschep.github.io/license-checker/

It does not fix the rate limit. But maybe it's so you can remember to come back and try again? Or it's for putting your own requests in the front of the queue.

Or it's just a cheap hack (and the author is lying) to get more exposure for your project.

From a "devil's advocate" perspective, it's a relatively simple way to keep people from burning through the rate limit by submitting loads of usernames. Of course, if checking whether a user has starred the repo counts towards the limit, it doesn't solve the problem entirely...

I used it and immediately unstarred.