PHP Notice: register_rest_route was called incorrectly.

Missing compatibility with the new WordPress version.

Error log outputs:

PHP Notice: register_rest_route was called incorrectly. The REST API route definition for wp-quiz/v2/video-content is missing the required permission_callback argument. For REST API routes that are intended to be public, use __return_true as the permission callback. Please see Debugging in WordPress for more information. (This message was added in version 5.5.0.) in …/wp-includes/functions.php on line 5311

WP Quiz says “Tested up to:5.5.3”