此消息不是WordPress核心的一部分。我通过在WordPress核心文件中搜索消息来证实这一怀疑。没有找到时，我用搜索引擎搜索了这条消息。您似乎正在使用New User Approve Message plugin.

此消息在中定义new-user-approve/includes/messages.php#L33

/**
 * The default message that will be shown to the user after registration has completed.
 *
 * @return string
 */
function nua_default_registration_complete_message() {
    $message = sprintf( __( \'An email has been sent to the site administrator. The administrator will review the information that has been submitted and either approve or deny your request.\', \'new-user-approve\' ) );
    $message .= \' \';
    $message .= sprintf( __( \'You will receive an email with instructions on what you will need to do next. Thanks for your patience.\', \'new-user-approve\' ) );
    $message = apply_filters( \'new_user_approve_pending_message_default\', $message );
    return $message;
}

add_filter( \'new_user_approve_pending_message_default\',
            \'wpse_new_user_approve_pending_message_default\' );
function wpse_new_user_approve_pending_message_default( $message ) {
    // Customize $new_message as needed and return it.
    $new_message = sprintf( __( \'New message...\', \'text-domain\' ) );

    return $new_message;
}