Extensions in GPX file cause exception

[mjpoo]

If the GPX file includes an extension in the metadata e.g.:

<metadata>
   <name>The Event Title</name>
   <author>
     <name>The Author</name>
   </author>
   <extensions>
     <oa:oaCategory>hikingTourTrail</oa:oaCategory>
   </extensions>
</metadata>

a Cannot read properties of null (reading 'getElementsByTagName') exception is thrown because it cannot find the name element.