apply_filters( 'wpmu_signup_blog_notification_subject', string $subject, string $domain, string $path, string $title, string $user_login, string $user_email, string $key, array $meta )

Parameters

$subject

Subject of the notification email.

$domain

Site domain.

$path

Site path.

$title

Site title.

$user_login

User login name.

$user_email

User email address.

$key

Activation key created in wpmu_signup_blog().

$meta

Signup meta data. By default, contains the requested privacy setting and lang_id.