The developers behind the new proposal, BastionZero co-founder Ethan Heilman and Botanix Labs lead software engineer Armin Sabouri, describe their refreshed version of OP_CAT as a simple piece of coding – just a dozen or so lines. They say it could provide the general-purpose functionality that’s been missing from Bitcoin since its very early days, and that’s been a key driver of growth on Ethereum, the second-biggest blockchain. If launched, so-called layer-2 networks might be easier to build atop Bitcoin, along with other innovations like decentralized exchanges or file hosting.