Really? I was under the impression that most language package managers downloaded from a CDN. I know that pip, npm, yarn, cargo, and hex do, at least.

Homebrew I believe goes through GitHub. Many of the Vim plugin managers also do, or at least have the option. I think CocoaPods and Carthage, both for iOS development, do as well.

I think it's somewhat common for a new package manager to use Github as a kind of CDN for a while, until they get big enough they can do their own.

Thanks for the explanation.