Manual:Hooks/SaveUserOptions

Details

 * $user: The user for which the options are going to be saved
 * &$modifiedOptions: The user's options as an associative array, modifiable. To reset the preference value to default, set the preference to null. To block the preference from changing, unset the key from the array. To modify a preference value, set a new value.
 * Note: $modifiedOptions can contain options whose values haven't changed.
 * i.e. If there is option = false and later on it is set again to option = false, it's still added to $modifiedOptions even if the value itself hasn't changed.
 * $originalOptions: The user's original options being replaced