gitlab-org--gitlab-foss/app/assets/javascripts/sidebar/queries/merge_request_subscribed.query.graphql

query mergeRequestSubscribed($fullPath: ID!, $iid: String!) {
  workspace: project(fullPath: $fullPath) {
    __typename
    issuable: mergeRequest(iid: $iid) {
      __typename
      id
      subscribed
    }
  }
}