wp-includes/php-ai-client/src/Files/ValueObjects/MimeType.php:150Checks if a MIME type string is valid.
$mimeTypestringbool public static function isValid(string $mimeType): bool { // Basic MIME type validation: type/subtype return (bool) preg_match('/^[a-zA-Z0-9][a-zA-Z0-9!#$&\-\^_+.]*\/[a-zA-Z0-9][a-zA-Z0-9!#$&\-\^_+.]*$/', $mimeType); }Introduced in 0.1.0. Unchanged from 7.0.4 through 7.1.0.
Signature, return type and hooks compared across 2 parsed releases.
src/wp-includes/php-ai-client/src/Files/ValueObjects/MimeType.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.