The abstract class ChangeModificationNotificationJob has two concrete implementations, ChangeDeletionNotificationJob and ChangeVisibilityNotificationJob. All three of them use LBFactory in some way.
ChangeModificationNotificationJob uses it with
$this->lbFactory->getMainLB()->getConnection( DB_REPLICA );
and the two concrete implementation use it with
$dbw = $this->lbFactory->getMainLB()->getConnection( DB_MASTER );
(We maybe could use this opportunity to replace the deprecated constant DB_MASTER with DB_PRIMARY.)