System Stream is the system's built-in stream that generates queries dynamically; to use System Stream, go to Menu → Preferences → Streams and enable it.
System Stream
description
Team Stream
Issues on GitHub where your team mentioned
Watching Stream
Issues in the repositories you're watching on GitHub
Subscription Issue
Individually registered issues
The Team Stream allows you to get the teams you belong to on GitHub and handle issues where they are mentioned. When you join a new team, the team will be added automatically.
The Watching Stream can retrieve repositories that you have watched on GitHub and handle issues in those repositories. When you watch a new repository, it will automatically add it to your repository.
The Subscription Stream provides the ability to handle individually registered issues. Register the URL of the issue from the Subscription Stream menu.