Recently I saw this field in my heroku application settings.
Link your app to a GitHub repository to see commit diffs in the activity log.
I tried to add ‘myusername/myrepo’ in this field, but it didn’t change anything in activity log. How can I use this setting? And for what?
It’s subtle, but your activity log has changed. When you add a repository in Heroku settings, the commit hashes in your activity log turn into links to GitHub, like so: