A typed personal attribute value.
The three temporal types are three variants, and none of them is "an instant with an optional zone" ([ADR-183]). The meaning is carried by which variant it is, never by whether a field happens to be filled in, so there is no reading of a stored value that could go two ways.
[ADR-183]: ../../../docs/decisions/ADR-201-225.md#adr-206-timemodel--koru-has-three-temporal-types-not-one-with-a-nullable-timezone
