Issue using expo and expo go on the lan

[john doe <johndoe65534@mail.com>]

Debians,

I'm required to use 'expo' as a server and to use the 'expo go' app on a
android device to create apps

On Bullseye, I have installed 'nodejs' and 'npm' 'expo-cli' using 'npm'.

I have created an new app with 'expo init myapp' then I do:
$ cd myapp
$ expo start
This starts the "server" and I can access it at the specified URI
(http:://xxx.xxx.1.5:19000) from a web browser.
Strangely, I see the content of the file app.json but not the app it self.

I have a fiew questions:
- Why am I seeing the content of the *.json file and not the app (I
would like to see the app on android an at the same time in the browser)?
- Do I need to open other ports than the one shown when starting the
server (per default 19000)?
- The android device can't access the server at 'exp://xxx.xxx.1.5'?


Any feedback is appriciated.

--
John Doe