wp-includes/php-ai-client/src/Files/ValueObjects/MimeType.php:251Gets the string representation of the MIME type.
string public function __toString(): string { return $this->value; }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.