I have MediaWiki version 1.41 and want to Install https://www.mediawiki.org/wiki/Extension:Page_Forms. I followed the download instruction from https://www.mediawiki.org/wiki/Extension:Page_Forms/Download_and_installation and executed:

 git clone https://gerrit.wikimedia.org/r/mediawiki/extensions/PageForms.git

Which results in the webbrowser to the following error message:

I changed the extension name from ‘Mediawiki_PageForms’ to ‘PageForms’ but without any difference.

What can be the reason for this error and how to resolve it?