Great Overview of Polygon System 4:00 milestones api snapshots to deal with reorgs 18:00 agg layer public good no rent seeking 19:22 unified bridge, (lh no ibc path like dependency of token?) but how can be fungible with chain halts and different secirty levels-pessimistic proof handles this maybe? 27:26 caveat rebase tokens etc cannot be handled by agg layer currently, would need special code on each chain