This is a major pain point in my company, so I'm curious about the experiences elsewhere: do you mean that Figma tracks changes between "saves", ala google docs, and one can go back in time and see the whole thing as it was yesterday, or you mean it's possible to see a comparison of what changed, akin to Confluence or (of course) version control systems?
Just the Time Machine part I'm afraid. Diffing would be fantastic though for sure, I can think of several times that would have been useful in my team too.