gitlab/ee/app/assets/javascripts/boards/graphql/update_epic_labels.mutation.graphql

mutation updateBoardEpicLabels($input: UpdateEpicInput!) {
  updateEpic(input: $input) {
    epic {
      id
      labels {
        nodes {
          id
          title
          color
          description
        }
      }
    }
    errors
  }
}