wp-includes/class-pop3.php:613$cmdoptional"" function is_ok ($cmd = "") { // Return true or false on +OK or -ERR if( empty($cmd) ) return false; else return( stripos($cmd, '+OK') !== false ); }Unchanged from 6.7.7 through 7.1.0.
Signature, return type and hooks compared across 5 parsed releases.
src/wp-includes/class-pop3.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.