@Martin I was a bit busy last days so I missed your messages. I'm catching up

@Martin this works now for me: lackadaisical-appeal.glitch.me/hnq/mathoverflow.net but that probably is because there is an hot question in top 100 of hot questions across the network.

The tool doesn't gather the hot questions from all sites, it relies on the SE HNQ feed. If there are no questions from a site that reach the Hot threshold, they won't appear in the HNQ feed and then it won't return items in the rss feed if you filter for that site.

Your syntax was fine, there must not have been hot questions when you tried.

@Martin yes, the '"match domainname" is not very strict. It basically is a CONTAINS('math') or a url LIKE '%math%' in sql. Using the complete site url guatantees you're getting results from the specific site (given there are hot questions)