I hadn't heard of this, but it's nice to see that it's standardized (although I'm not really prepared right now to evaluate that standard properly).
Some time ago (9 years, apparently - time sure does fly), I made a thing to describe patches to a binary using JSON (https://github.com/zahlman/json_bpatch). It was meant primarily for hacking content into someone else's existing binary file, and I spent way too much time on fancy algorithms for tracking "free" (safely modifiable, based on the user's initial assessment and previous patches) space and fitting new content into the remaining space. Overall, I consider it a failure - but a fair amount of this project DNA is likely to survive in future projects.
I also had the idea at some point to make some kind of JSON diffing tool that works at a JSON-structure level instead of a textual level. I guess I don't need to reinvent that wheel.