I find this whole document hard to read. A "diff" colloquially refers to the difference between two things -- files, directory trees, whatever. What TFA refers to as a diff has been always known as a patch, at least to me.

This is nothing about diffs, but entirely about patch metadata management. I mean, sure, noble goal, but this is just shuffling bits around. If they proposed that metadata was required to be JSON that would be one thing, but instead it's some weird self-describing length-delimited nonsense that just disguises the same problems that exist today. It's already extensible! Just type words!

I've spent a lot of time parsing things out of git commits and patch files and while some standardization would be neat, this isn't it.

That said I find the argument that git diff style is more or less canonical more compelling than I have in the past. So there's that.

> A single diff can't represent a list of commits

A patch set can! Why on earth would you want that represented by a single diff is beyond me.