> The actual proving mechanism is either a) too amazing for me to understand or b) not quite figured out yet.
Rollups use either optimistic proofs or zero knowledge proofs for settlement
> The blob stuff is about "ok if that's a thing how do I prove to some L1 contract that I own these L2 funds?".
It's about data availability
> there's (supposedly) a way for you to slowly get your funds back by exiting on L1
They're called escape hatches, you can view the state of each L2 on L2Beat: https://l2beat.com/scaling/summary