Independent Guest Virtual Machine (IGVM) File Format

And this differs from ova ... how? (I mean, aside from the obvious EEE jokes, and their "but now in rust" peers)

I am always skeptical when someone yolos a new file format without a competitive analysis section, since (a) that makes it very hard for a consumer to know if their interests are aligned (b) it can often smell like NIH if the section is missing

By the look of it this format is designed to specifically support measurements to confirm the guest was loaded without modification, a la TPM style assertion of integrity.

I think you already answered the question.

https://xkcd.com/927/

How come a file format has a .cargo directory in the project tree?

It's defining build flags for the library containing the definition. I'd encourage people to read it, it's very documented by build flag standards: https://github.com/microsoft/igvm/blob/main/.cargo/config.to...