Passkey. @category-labs/mera returns a PRF secret. That secret becomes a BIP-39 mnemonic, then two secp256k1 keys at m/44'/60'/0'/0/0 (person) and m/44'/60'/0'/0/1 (agent). Each key signs its own message, Solarchik person or Solarchik agent, and the signature has to recover to that address. The credential id is stored in this browser under solarchik-passkey. It does not travel to another browser. No seed is rendered.