European Union lawmakers recently unveiled the Digital Markets Act, which aims to limit the power of “gatekeepers” — companies so big and popular that they shape entire industries — like the tech companies behind messaging apps. One rule would require that apps be “interoperable” with one another, so a startup, for instance, could let its users send messages to people using Apple’s iMessage or Meta’s WhatsApp seamlessly. Companies that don’t comply would face steep penalties — up to 20% of their global revenue. Alex Heath covers tech and internet platforms at The Verge. He laid out some of the pros and cons of the proposal.