How to identify the internal category Google uses for a Google Discover Post

This is a cool little trick I saw in a tweet from Valentin Pletzer. You can use this to identify the internal category Google assigns to Google Discover content.

I would use this to look at what category the discover post is coming from for content that I would like to potentially target. Google discover is a black box and any bit of info you can get can be useful, I am starting to collect a list of categories we come across.

Valentin has started collecting data in a spreadsheet that you might find useful.