Why would browser need to enumerate the installed apps?
Why?!
In other words, blame Google product management.
Instead of the browser enumerating all apps, why can’t it check when you visit a page if the current page (ONLY the current page) is installed as an app?
Maybe i’m missing something, but it sounds like it would be easy for google to support this functionality by letting developers configure this in their app “bundle”. A property that tells the OS “my app is related to domain example.com”. Make it an array of domains if you must.