To manage your integrations, click "Admin tools" -> "Service settings", then the "Integrations" tab.
# Removing an integration
To remove an integration, click the minus sign to the right. Not that this will not uninstall the GitHub app. To do so, head over to GitHub and manage the integration from there.
Not that uninstalling the app from GitHub will not automatically remove the corresponding installation shown in the image above, even though the app is no longer used. You can just go ahead and remove the installation from this view after uninstalling it.
Don't forget to click "Save" when you are done.