A Microsoft file hosting and synchronization service.
OneDrive is a cloud location of your docs/data
The default installation of Office 365 and its OneDrive component uploads all the contents of the PC \My Documents\ folders to OneDrive, (syncs) and there will be a OneDrive folder in File Explorer containing all the OneDrive content. And in Word etc the default Save location is set to OneDrive.
Via the OneDrive cloud icon on the task bar >Settings>Choose folders you exclude the game add-ons folder