I could imagine special features being a good reason for such a protocol, but the special features themselves might not be a good thing to have (i.e. IE's Activ

I could imagine special features being a good reason for such a protocol, but the special features themselves might not be a good thing to have (i.e. IE's ActiveX controls, that was 'special' too). Say you have an OS with functionality that depends on a webpage, and you don't want a user to end up clicking on a thing and not getting anywhere because the custom browser they installed was broken, that would be a reason to have a built in or 'fallback' browser, even if you just end up using it to install another browser. But then you could also have some form of checking if the user didn't get what they wanted and have a 'try again in Edge'-button or something like that. Might not be the best UX, so that's another factor. Is the UX for the masses, the UX for administrators or the UX for power users more important. I'm glad I'm not the person responsible for making those choices, but I'm curious about the processes and people that are on that path. Doubt MS will ever really publish that.