So, from the doc (Add-on: Home Assistant Google Drive Backup)
Integrates with Home Assistant Notifications, and provides sensors you can trigger off of if something goes wrong.
these are somehow injected ?
The add-on creates a few sensors that show the status of backups that you could trigger automations off of.
binary_sensor.backups_stalebecomes true when the add-on has trouble backing up or creating backups.