Under the hood, this application simply polls GitHub web endpoints (/pulls|/issues|/releases) of projects you specify, it doesn't require OAuth tokens or credentials entering into the extension.
GitHub Notifier is a tool in the Tools for GitHub category of a tech stack.
GitHub Notifier is an open source tool with 42 Github Stars and 10 Github Forks. Here’s a link to GitHub Notifier's open source repository on Github
Here’s a list of reasons why companies and developers use GitHub Notifier.