According to the Federation spec Entities that have @key(resolvable=false) should not be included in the _Entity union.
"The _Entity union must include all entity types that are defined in the subgraph schema, except entities with a @key that sets resolvable: false."
Spec Doc
The following code from the SchemaTransformer does not consider the resolvable field.
According to the Federation spec Entities that have @key(resolvable=false) should not be included in the _Entity union.
"The _Entity union must include all entity types that are defined in the subgraph schema, except entities with a @key that sets resolvable: false." Spec Doc
The following code from the SchemaTransformer does not consider the resolvable field.