Topic on Extension talk:CiteThisPage/Flow

After upgrading to MediaWiki 1.31, the special page "CiteThisPage" is empty. It shows just the page title, nothing else. How can I find out what is going wrong?

I used the special page ExtensionDistributor to download the extension CiteThisPage. The download for MW 1.31 does not work. The download for MW 1.30 works as expected.