For people who want to get a rough idea of what ISO 20022 is and how it looks like, I wrote a brief article about it from an end-user point of view: https://evrim.zone/blog/knowledge/iso_20022_pain_001

I think that it's a pretty handy format to be familiar with, and is quite simple to work with too.

If the Fed or participating banks decide to open up the system like European banks have done so, it can be handy to get familiar with it for us financial hackers out there!