X-WG-Include-Query-Plan to receive the query plan in the extensions field. The below headers are also useful
X-WG-Skip-Loader : Skip requests to subgraph, this will return data as null
X-WG-Disable-Tracing : This will ensure that requests for query plan are not traced in the router
Plans for @defer operations include the primary execution and every planned deferred branch. A request that combines X-WG-Include-Query-Plan: true with X-WG-Skip-Loader: true returns that complete plan in one JSON response with data: null; it does not execute subgraphs or require multipart response negotiation.
Cosmo Studio Playground showing the GraphQL query and its generated query plan