questions about OP Stack re-orgs:
- can unsafe blocks be re-orged by the sequencer?
- if so, how often are unsafe blocks re-orged?
- in practice how many confirmations before block become safe?
- is there a way to view historical re-orgs?
- (bonus) what's the best way to detect a re-oreg?

I’ll skip the first couple because Roberto did a good job answering them. The number of confirmations before a block becomes safe depends on how often the OP Stack chain posts batch transactions of L2 state. Once your L2 txs are posted to Ethereum, they’re considered safe and once the L1 block with that tx data is finalized on L1 you can consider it finalized and will not ever be reorged. Here’s a pretty good doc on the topic

@farcaster dev / dad / books, cooks, ski, code ~ there are many things of which a wise man might wish to be ignorant

I’ll skip the first couple because Roberto did a good job answering them. The number of confirmations before a block becomes safe depends on how often the OP Stack chain posts batch transactions of L2 state. Once your L2 txs are posted to Ethereum, they’re considered safe and once the L1 block with that tx data is finalized on L1 you can consider it finalized and will not ever be reorged. Here’s a pretty good doc on the topic https://docs.optimism.io/stack/transactions/transaction-finality