The browser — long the stoic conduit between users and the web — has been remade as an assistant-first platform in 2025, with OpenAI, Microsoft, Perplexity, The Browser Company, Opera and Brave all racing to ship browsers or browser modes that embed large language models and agentic assistants at the UI layer: persistent sidebars, multi‑tab context, cursor chat, and agentic “do this for me” features that can click, fill, and transact on users’ behalf. These changes promise major productivity...