title: UploadBase.php setting to save SVG file on mediawiki
body: <p>I'am using an addon on my wiki, to edit svg files on the fly: but now I had this problem; A user copy and paste a diagram from drawio and try to pase on the wiki and this error appears:</p>
  
  <pre><code>The wiki returned the following error when uploading: Found href to unsafe data: URI target"" in the uploaded SVG file.
  </code></pre>
  
  <p>How can I avoid this in my <code>UploadBase.php</code> last time the URI got an url on the target (the url was <a href="http://www.w3.org/1999/xhtml" rel="nofollow noreferrer">http://www.w3.org/1999/xhtml</a>), so I did this:</p>
  
  <pre><code>static $validNamespaces = [
                          'adobe:ns:meta/',
                          'http://www.w3.org/1999/xhtml',
  </code></pre>
  
  <p>And this worked just fine: but what about an empty one?</p>