Changes
Stay posted about past changes
Now and then visit the release notes which may be a little behind on the actual changes
Feeds can alert you about changes in the project files and release notes.
The sources of the help pages (or any other file) have a history button and a blame button.
The latter shows who was the last to touch a line, might be just a space or typo.
Stay posted on discussions
To receive email alerts about discussions: use the “watch” button almost on top of the project page.