Delta Live Tables leverage Delta Lake, or Delta Tables.  Delta tables, through transactions (e.g. insert, update, delete, merges, optimization) create versions of said Delta Table.  Once a version is created it cannot be altered, it is immutable.  You can always roll back (restore) to an ealier version of the Delta table, this action will create a new version of the table.  The older versions will always be present unless vacuum is run.

Hope this helps.

Louis