Once upon a time I used privoxy. It was a local HTTP non-caching proxy that let you process HTML requests and came with adblocking scripts you could enable. There were certain advantages to that model compared to current browser plugins. But I'm happy to pay no privoxy as a cost of HTTPS. There's reasons for that though: e.g. today, web browsers generally act as platforms that allow us to write ad blockers inside them. Will I be able to plug into my own DNSoTLS clients?