He used to own the keys to Bitcoin Core. Not sure what he is doing now.
Helps that you reminded me in your latest episode which I'm listening to now.
BTW he did a horrible job at the start of the episode in explaining Kaspa. I had to Google that it's an L1. You shouldn't let your guests explain the top level basics. Stefan Livera does a good job of that, although I disagree with him on most things.