You can also perform this programmatically by leveraging the GitHub API. There's a whole section dedicated to the Package Download API.
Below the syntax to retrieve the list of downloads
GET /repos/:user/:repo/downloads
For instance here are the list of downloads of the libgit2 project:
- Web: https://github.com/libgit2/libgit2/downloads
- API: https://api.github.com/repos/libgit2/libgit2/downloads