@duncan_richards12 is right! If you think about it, there’s no other way we could implement this: if you’re using our hosted service, dependencies are other apps also on our hosted service, so we can automatically pull together all the source code you need when we’re serving your app.
The App Server is a truly standalone program - it doesn’t have any hidden “phone home” machinery for downloading and running code from us (if it did, that would be cool but not particularly independent from our service, which would erase a lot of the benefits). So all the source code your app is going to use needs to be downloaded onto the machine where it’s running!