ISO-8601 timestamp of the write.
The definition that produced the value (for
DerivedPropertyEngine, the definition's name).
OptionalexpressionThe expression text at write time, so a reader can see the rule even after the definition changed or went away.
OptionalversionThe definition's version when the value was written. A stamp whose version is older than the definition's current version is STALE: the rule changed and the value has not been recomputed.
Provenance stamp for a DERIVED node property value (issue #17).
Held in a sidecar registry on the UGM, keyed by node id and property name, never on the node's attributes: a stamp inside
propertieswould itself be a property (a column, an export field, an encoding driver), which is the laundering the stamp exists to stop. The stamp names the definition that wrote the value; the value stays a plain property so every existing reader keeps working.