ghinstallation中的GitHub应用程序的集成ID是什么？

I am trying to create a GitHub App in Golang by using a library named ghinstallation. As the description showed below, Integration ID and Installation ID are required.

// Wrap the shared transport for use with the integration ID 1 authenticating with installation ID 99.
itr, err := ghinstallation.NewKeyFromFile(tr, 1, 99, "2016-10-19.private-key.pem")
if err != nil {
    log.Fatal(err)
}

I think the Installation ID is exactly the ID appears in the URL(https://github.com/settings/installations/:installation_id). However, I've no idea what the Integration ID is.

The GitHub App Integration ID is the ID of your GitHub App. You can find it in the "About" section in the "General" tab of your GitHub App.