Unknown values

getDevice() returns undefined when the exact, case-sensitive Product Identifier is absent. getDeviceModelName() behaves the same way. Callers choose their own fallback presentation.

getOsVersion() always preserves the trimmed build value. Its known discriminant prevents an unknown build from being mistaken for a confirmed version:

const result = getOsVersion({ productIdentifier, build });
if (!result.known) {
  display(result.build);
}