Starknet has released plans to settle simultaneously on Bitcoin and Ethereum, becoming a single self-custodial decentralized L2. StarkWare is launching a $1 million fund to spur the development and introduction of OP_CAT, the Bitcoin opcode needed to make a trustless L2 possible. Beyond scaling Bitcoin to thousands of transactions per second, simultaneous settlement would allow for BTC/ETH atomic swaps and private BTC transactions, along with many other possibilities.