wp-admin/includes/class-wp-screen.php:477Sets the old string-based contextual help for the screen for backward compatibility.
$screenWP_Screen$helpstring public static function add_old_compat_help( $screen, $help ) { self::$_old_compat_help[ $screen->id ] = $help; }Introduced in 3.3.0. Unchanged from 6.7.7 through 7.1.0.
Signature, return type and hooks compared across 5 parsed releases.
src/wp-admin/includes/class-wp-screen.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.