Gold that is nobody's, yet

Every balance you have met so far belongs to an account. A claimable balance belongs to no one: it is a ledger entry of its own, holding an amount, naming who may take it, and under what condition.

The sender no longer has the gold. The claimant does not have it either — not until they reach in. In between, it sits on the ledger, visible to everyone, spendable by exactly one address.

That is how escrow, airdrops, vesting and "here, take this when you're ready" all get built without a single line of contract code.