Ka on Nostr: How does this work

{ "id": "5918ada9a55cff6837c2f0c89d068c0e61c83c36f9b33dec40d1c034eb5f97f7", "pubkey": "484d000d9a78051d24660b6e6ca437f0f218e3b40f0d8c0032ab2872c7cf24b1", "created_at": 1688242269, "kind": 1, "tags": [], "content": "How does this work", "sig": "7dfba64c86713d2bf72428ca2faf97e79778c103e23c4845141fb36fa7899a6ee085bbc9fa0c7cdcd1f1f6bb0e0497f8d1e4a2b7d8df60ca6bc564629edcfd2a" }