Launch external app: web browser with local file

1. What is the problem? Be very detailed.
I am trying to open a local html file by calling the device's web browser with ODK collect. I am using the External app feature for that and I pass the path to the file as described here:
https://docs.getodk.org/launch-apps-from-collect/#id4
.
I have successfully launched the web browser on the device when the uri_data was a link to a website. But when I set the path to a local file, I get "the request application is missing"
2. What app or server are you using and on what device and operating system? Include version numbers.
ODK Central, ODK Collect 1.28.4, on Android 11 Tablet

So far I have tried the following options in the APPEARANCE field without succes:
ex:android.intent.action.VIEW(uri_data='file:///Website/AlmSom.html')
ex:android.intent.action.VIEW(uri_data='file:///Tablet/Website/AlmSom.html')
ex:android.intent.action.VIEW(uri_data='Website/AlmSom.html')

what is working is:
ex:android.intent.action.VIEW(uri_data='https://www.example.com/en/')

I'm pretty sure that recent Android OSes don't let apps read arbitrary files from the local file system. You might be able to run a small web server on device and connect to that.

Also if you just want to open links, might be easier to use the url widget or markdown links.

Dear yanokwa,

Thank you for your help, but I don't think it is necessary to make it that sophisticated.
Android has the system internal app "webview"

Whis is exactly made for this purpose: displaying webpages inside an app. It can also display local files, as is noted here:

I still have not managed to make it work. My intents lead to a "application not found" message where number keyboard shows up.

Does someone now the right intent to make it work?

Do I need to add additional namespaces directly in the XML file to make it work?

Is it possible that the reason you have not managed to get to work is that it is necessary to make it as sophisticated as I suggested?

If you want to read HTML files that are inside your application (e.g., in your assets folder), then WebView will work on most Android devices. If you want to read local HTML files from anywhere on the file system, then WebView will not work, at least for recent versions of Android.