[4.x] How to use languageNegotiation with "GraphQL operation context"

Hello guys,

For my client project, I set up a drupal multi language website and I want to use graphql to proposes contents, paragraphs, taxo and medias entity.

I saw in back-office in "Detection and selection" page, an option "GraphQL operation context", but I don't know how use it.

Can you explain me the right way to use this?

Thank a lot