Filters the subject of the notification email of new user signup.
$subjectstring$user_loginstring$user_emailstring$keystring$metaarraywp-includes/ms-functions.php:1156wpmu_signup_user_notification() * @param string $subject Subject of the notification email. * @param string $user_login User login name. * @param string $user_email User email address. * @param string $key Activation key created in wpmu_signup_user(). * @param array $meta Signup meta data. Default empty array. */ apply_filters( 'wpmu_signup_user_notification_subject', /* translators: New user notification email subject. 1: Network title, 2: New user login. */ _x( '[%1$s] Activate %2$s', 'New user notification email subject' ), $user_login, $user_email, $key,Introduced in MU (3.0.0). Unchanged from 6.7.7 through 7.1.0.
Signature, return type and hooks compared across 5 parsed releases.