code: @Nonnull
    public EChange clearCache ()
    {
      return m_aRWLock.writeLocked ( () -> {
        EChange ret = m_aList.removeAll ();
        if (!m_aMapExt.isEmpty ())
        {
          m_aMapExt.clear ();
          ret = EChange.CHANGED;
        }
        if (!m_aMapMimeType.isEmpty ())
        {
          m_aMapMimeType.clear ();
          ret = EChange.CHANGED;
        }
        return ret;
      });
    }
docs: Remove all registered mime types
  
  @return {@link EChange}.