Manual:User former groups table

Schema summary
mysql> describe mw_user_former_groups; +---+--+--+-+-+---+ +---+--+--+-+-+---+ +---+--+--+-+-+---+ 2 rows in set (0.11 sec)
 * Field    | Type             | Null | Key | Default | Extra |
 * ufg_user | int(10) unsigned | NO   | PRI | 0       |       |
 * ufg_group | varbinary(16)   | NO   | PRI |         |       |