NIP-07
Browser extension signing
NIP-07 lets a browser extension act as your Nostr signer. The website can ask the extension to identify you or sign an event, but the private key stays inside the extension instead of being typed into every site you visit.
A simple analogy is a chip-and-PIN card reader: the shop asks for approval, but it does not get to keep your card secret. This makes web clients more convenient while reducing the chance that a random website stores your private key.
Read more in the official 07.md NIP document.