title: TYPO3: plugin not showing up in backend
body: <p>This is T3 v7.7.25 and I tried to build my first extension. The idea is to have a selectable content element in the backend whose html template file does nothing but a php echo.</p>
  
  <p>My emconf:</p>
  
  <pre><code>&lt;?php
  
  $EM_CONF[$_EXTKEY] = [
          'title' =&gt; 'Robert PHP',
          'description' =&gt; 'An extension to use PHP.',
          'category' =&gt; 'plugin',
          'author' =&gt; 'John Doe',
          'author_company' =&gt; 'John Doe Inc.',
          'author_email' =&gt; 'john.doe@example.com',
          'state' =&gt; 'alpha',
          'clearCacheOnLoad' =&gt; true,
          'version' =&gt; '0.0.0',
          'constraints' =&gt; array(
              'depends' =&gt; array(
              'extbase' =&gt; '6.0',
              'fluid' =&gt; '6.0',
              'typo3' =&gt; '6.0',
              )
          )
  ];
  </code></pre>
  
  <p>My ext_tables:</p>
  
  <pre><code>&lt;?php
  
      if(!defined('TYPO3_MODE')) die ('Access denied.');
  
  
      \TYPO3\CMS\Extbase\Utility\ExtensionUtility::registerPlugin(
          $_EXTKEY,
          'Robert',
          'Beschreibung fuer Auswahl'
      );
  </code></pre>
  
  <p>My localconf:</p>
  
  <pre><code>&lt;?php
  
      if(!defined('TYPO3_MODE')) die ('Access denied.');
  
      \TYPO3\CMS\Extbase\Utility\ExtensionUtility::configurePlugin(
          $_EXTKEY,
          'Robert',
          array(
              'Php' =&gt; 'include'
          ),
          array()
      );
  </code></pre>
  
  <p>My controller:</p>
  
  <pre><code>&lt;?php
  
      class Tx_RobertPhp_Controller_PhpController extends \TYPO3\CMS\Extbase\Mvc\Controller\ActionController
      {
          public function includeAction() {
  
          }
      }
  </code></pre>
  
  <p>My template:</p>
  
  <pre><code>&lt;?php
  echo "echo aus der ext";
  ?&gt;
  </code></pre>
  
  <p>I cannot choose the plugin in the backend, so something must be wrong with registerPlugin. But since I see no error message I find it very hard to track down the problem?</p>