How to use adminer without password basing on login-password-less plugins

I want to use adminer without password.
I uploaded adminer-4.7.7-en.php file and finding login-password-less plugin
I create file plugins/login-password-less.php with content :

class AdminerLoginPasswordLess {
    /** @access protected */
    var $password_hash;
    /** Set allowed password
    * @param string result of password_hash
    function __construct($password_hash) {
        $this->password_hash = $password_hash;
    function credentials() {
        $password = get_password();
        return array(SERVER, $_GET("username"), (password_verify($password, $this->password_hash) ? "" : $password));
    function login($login, $password) {
        if ($password != "") {
            return true;


and reading I created file adminer.php, which is
located in one dir with adminer-4.7.7-en.php and I created new apache host pointed at this file.

function adminer_object() {
    // required to run any plugin
    include_once "./plugins/login-password-less.php";
    // autoloader
    foreach (glob("plugins/*.php") as $filename) {
        include_once "./$filename";
    $plugins = array(
        // specify enabled plugins here
        new AdminerLoginPasswordLess(hash("md5", 'my_sql_user_password')),
        //Is the selected "md5" method valid ?
    return new AdminerPlugin($plugins); // I am not sure which class is it and where it is defined ?
// include original Adminer or Adminer Editor
include "./adminer-4.7.7-en.php";  // encoded file I uploaded


But I got error :

Fatal error: Uncaught Error: Class 'AdminerPlugin' not found in /mnt/_work_sdb8/wwwroot/lar/local_adminer/adminer.php:32 Stack trace: #0 /mnt/_work_sdb8/wwwroot/lar/local_adminer/adminer-4.7.7-en.php(1654): adminer_object() #1 /mnt/_work_sdb8/wwwroot/lar/local_adminer/adminer.php(36): include('/mnt/_work_sdb8...') #2 {main} thrown in /mnt/_work_sdb8/wwwroot/lar/local_adminer/adminer.php on line 32

Code (markup):

Which class AdminerPlugin is it and where it is defined ?
How to fix this issue?