ohmu/third/drupal/mustikas11/revoke_anon_access.php

<?php
use Drupal\user\Entity\Role;

$role = Role::load('anonymous');
if (!$role) {
  echo "ANON_ROLE_NOT_FOUND" . PHP_EOL;
  exit;
}

// Eemalda access content (D7-s anonüümne seda ei omanud).
if ($role->hasPermission('access content')) {
  $role->revokePermission('access content');
  $role->save();
  echo "REVOKED access content" . PHP_EOL;
} else {
  echo "ALREADY NO access content" . PHP_EOL;
}

echo "Anonymous permissions: " . implode(', ', $role->getPermissions()) . PHP_EOL;