GitHub specifics

GitHub has an API endpoint here. But if you're here, then you know how it sucks:

A release would show up in this API response only if it was filed formally using the GitHub release interface. Sometimes project authors use formal releases, and the next thing you know, for the next release they won't.

OK, you think you could use another API endpoint to list tags. Tags usually represent a release, however, the API does not sort them chronologically. Moreover, you might get something like "latest-stable" for a tag name's value (typical not just for GitHub).

lastversion uses GitHub feeds combined with all the above API endpoints to make a fast and rational decision on what is truly the latest version.