tl;dr: Cloudflare built Kitesurf, a lightweight browser designed for AI agents that runs entirely on Workers using V8 isolates, WebAssembly, and Rust-based components like Blitz and Stylo instead of Chromium. It trades pixel-perfect rendering and features like video/WebGL for 3-7x lower CPU and memory usage, though it's currently ~1.7x slower in wall time. Available in beta via Browser Run with CDP compatibility (Puppeteer, Playwright, MCP), it passes 215,000+ Web Platform Tests and will be open-sourced eventually.