Keep tabs on any file in any public GitHub repository
Watching a repository on GitHub tells you about social activity (e.g. PRs, issues, etc.), but it doesn't let you know about file-level changes you might care about (e.g. changes to an internal API you're abusing, to a SQL structure, to a dependencies file).
GitHub File Watcher fills that gap. Just enter your email, the GitHub repository you want to track, and what files you want notifications for. When they change, you get an email.
Tip: you can pass repository, email, and glob as GET parameters to pre-fill those fields.