Which browser do I need for web4:// addresses?

You need a Web4-capable browser. Ordinary browsers do not resolve the web4:// protocol.

BRIDGE: BRIDGE is a browser built to open web4:// addresses.

Other browsers: We hope that further browsers will add support over time. Nothing is confirmed, and until then a Web4-capable browser is required.

Why a different protocol at all: LNS names are tied to your Web4 identity rather than rented from a registrar, which is not something the traditional https:// address system was built to express.