Ask HN: What hyper-focused industry newsletters do you enjoy?

In my experience, HN users tend to have incredibly specialized interests. I'm curious about what newsletters are out there that deliver a depth of specialized knowledge?

For me, it doesn't get better than 'The Prepared' and the 'Future of Trucks' newsletters. Both provide a window into technicalities that I wouldn't otherwise think about in fields that I'm broadly interested in.

https://theprepared.org/ https://www.trucks.vc/newsletter