According to Microsoft Graph "Groups are collections of principals with shared access to resources in Microsoft services or in your app."
However you can also get driveItems inside a group, e.g. GET /groups/{group-id}/drive/items/{item-id}
Which seems to give you access to driveItems which were created in sites associated with Microsoft Teams, however not driveItems in normal Sharepoint sites.
What exactly is the relationship between groups, sites and driveItems? e.g. is it always true that a Teams site will have a group which can contain driveItems, and Sharepoint sites never have groups but can have driveItems?
