This site describes solve-engine as it is on main: 2.43.0, which npm does not have yet. npm installs 2.40.0, so a page may show an answer that version does not give yet.
WorkerWhatIfOverrides
type WorkerWhatIfOverrides = Readonly<Record<string, number | string>>;Defined in: packages/engine/src/worker/protocol.ts:46
A what-if’s overrides as they cross the boundary: each a finite number, or
text the worker evaluates on its own ("$120", "5%"). A Value cannot
cross postMessage with its type intact, so its text form is sent instead.