App Platform component to component requests

I’m interested in hosting an Nginx reverse proxy on App Platform via Docker which will be used to proxy requests to other components in the same app and enforce rate limits.

I’ve seen a few references to internal communication via App Platform:

1. How to call an App from another service / app?
2. How to run single nginx and multiple Laravel instances in the App Platform
3. How should I implement proxying and redirects on the app platform?

I can’t find any official documentation about the App Platform internal routing feature, but the consensus seems to be a component in App Platform can send requests to other components within the same app via http://component-name.

For example, consider an App Platform app with the following components:

1. Nginx reverse proxy named nginx (Web Service)
2. Rails server named rails-server (Web Service)
3. Go server named go-server (Web Service)

It appears as though Nginx can proxy requests to the other components by listing http://rails-server and http://go-server in a proxy_pass rule.

My questions are as follows:

1. Where can I find App Platform documentation for this feature?
2. Do components in an App Platform application exist within a VPC?
3. Are component to component requests such as http://${component-name} routed on the public Internet?

The internal routing functionality seems like quite a feature but I’m concerned about the fact that I can’t seem to find documentation for it.