GitCDN.xyz has been read-only and the site has been down, might want to use jsDelivr instead.

The "https://gitcdn.xyz/repo/pedroborges/xml-sitemap-stylesheet/master/sitemap.xsl" is not loading. I don't see anything wrong with it though

I think it is best to leave the default sort to match the order in the XML file, but add a JS table sorter.

Your intro starts with "Simply add this line to your page". But its not as simple as that. Since the file needs to have correct structure of how the sitemap is made. I tried one setup using sitemap.org and returns complete blank page. Then tried only using your stylesheet, i do get something, but it doesnt build the page properly