Extension:UserMerge/Hooks/MergeAccountFromTo

Details

 * &$fromUser: user object of the "merge from" (source) account
 * &$toUser: user object of the "merge to" (target) account

Used to update user data stored by extensions. If the only update needed is to change the user ID or name (no records need to be merged etc.), UserMergeAccountFields is a better alternative.