When CubeBackup creates a backup snapshot, does it backup all data each time, or only the changes?

Incremental algorithm

CubeBackup employs an incremental backup algorithm, so that only new or modified data is backed up each time.

Google Workspace backup snapshot

CubeBackup behaves much like Git or Mac OS Time Machine, keeping all historical versions of your data in snapshots. Actually, CubeBackup employs a SQLite database to track changes, so that it understands the full version history of all Google Drive files and folders, Google Contacts data and Google Calendar events in your Google Workspace.