ValueModelBackfill

The last moment re-valued, included; null when you sent no period.

Signals re-valued, across all customers (signals for a customer that doesn't exist yet aren't counted).

The first moment re-valued; null when you sent no period.

Values stored, one per signal and metric that valued it; more than valuedSignalCount when signals feed several metrics.

Of those, the signals at least one metric valued.

The value model in force now (vm_unversioned before the first version).

Its version number.