List of Atom (Web syndication) links to monitor a repository and more on Github.
Just replace the variables ${…} by there corresponding content.

Repository releases:

https://github.com/${owner}/${repository}/releases.atom

Repository tags:

https://github.com/${owner}/${repository}/tags.atom

Repository commits:

https://github.com/${owner}/${repository}/commits.atom

Private feed (you can find Subscribe to your news feed in dashboard page after login):

https://github.com/${owner}.private.atom?token=${secret}

User activity:

https://github.com/${user}.atom