[codethief]

> A property that tells the OS “my app is related to domain example.com”. Make it an array of domains if you must.

Elaborating on the sibling's comment: There is already such a property that apps must set in their manifests in order for them to be able to react to links/intents for domain-associated-with-the-app.com.

But it doesn't address the question of how a browser is supposed to be able to open links to domain-associated-with-the-app.com in that app, without Android revealing to the browser whether the app is installed or not. In short: The browser will, by construction, be able to determine which apps you've got installed or not.

[pizza]

I mean, do Windows or macOS tell the browser which mail apps you have installed when it handles a mail:// URI?

[josephg]

No, but web browsers do have the ability to ask the OS which application is associated with a certain url type.

But it doesn’t leak that information to web pages.