wasm entry point?

I have written part of a wasm reader, leading up to an interpreter.

In example helloworld that runs in a browser, I can't figure out what is the entry point.

The start section is absent.
Main is not exported unless you use -g.
There seems to be no way the .html/.js can get to main, yet it does.

How?

For now I'll require -g and find it via named export.

Thank you,
  - Jay