Error:  Data structure returned is not convertible in the requested format. Try to call this method with the parameters '&amp;format=original&amp;serialize=1'; you will get the original php data structure serialized. The data structure looks like this: 
 $data = array (
  'name' =&gt; 'HashUserId',
  'description' =&gt; 'Anonymize UserId using salt and sha1 hash.',
  'version' =&gt; '0.4.0',
  'license' =&gt; 'GPL v3+',
  'theme' =&gt; false,
  'homepage' =&gt; 'https://github.com/iMarkus/Piwik-HashUserId',
  'require' =&gt; 
  array (
    'piwik' =&gt; '&gt;=3.0.0,&lt;4.0.0',
    'php' =&gt; '&gt;=5.6.0',
  ),
  'authors' =&gt; 
  array (
    0 =&gt; 
    array (
      'name' =&gt; 'iMarkus',
      'email' =&gt; 'iMarkus@users.noreply.github.com',
      'homepage' =&gt; 'https://github.com/iMarkus',
    ),
    1 =&gt; 
    array (
      'name' =&gt; 'hagor',
      'email' =&gt; 'hagor@users.noreply.github.com',
      'homepage' =&gt; 'https://github.com/hagor',
    ),
  ),
  'support' =&gt; 
  array (
    'issues' =&gt; 'https://github.com/iMarkus/Piwik-HashUserId/issues',
  ),
  'keywords' =&gt; 
  array (
    0 =&gt; 'Anonymize',
    1 =&gt; 'Hash',
    2 =&gt; 'UserId',
  ),
);