Referencing Plasmic components/page props in GraphQL query

How to reference a Plasmic component/page prop in a GraphQL query?
like @yang mentioned here:

When selecting a graphql thatcher component, do you see a prop called variable overrides? That’s where you can pass in an object of variable names and values, and you can reference whatever you want in there

Ah! I see it in the sidebar of the GraphQL Fetcher component
In my case, I’ve been using the Hygraph/GraphCMS Fetcher though, which does have a “Query Variables” section but that doesn’t seem to like calls to $state or $props :confused: