https://x401.proof.com/spec/latest/#abstract

in a nutshell:

* a website that wants to authorize who you are (say, to book a flight or sign a waiver for go kart rental)

* the endpoint returns 401 and defines in a header what info it needs about you (over 18? you're actually John Doe? etc.)

on the proof side specifically, we're putting IAL2 verification in front of this https://pages.nist.gov/800-63-3-Implementation-Resources/63A...

pretty cool stuff, its early days but its a strong way to ensure there's a human authorizing sensitive actions an agent is taking on your behalf