Note that there is no need for this on Android, because Android doesn't seem to have protocol handler prompts.

I'm unsure that this should block anything. I guess the main problem is that it is in a bubble which points at the page info button, which implies it can be changed under there.

Currently it can't be changed under there but you can hit 'site settings' to get to a page where you can click on a link and change it.

Introducing a site details page without handlers, and pointing the button on page info there would make it slightly worse, as you'd have to hit back before you could then click on the link to the handlers page. But I think making this a blocker on introducing site details is unnecessary as it is only slightly worse and this is a very rarely seen permission bubble.

> Introducing a site details page without handlers, and pointing the button on page info there would make it slightly worse, as you'd have to hit back before you could then click on the link to the handlers page.

I think it's very bad for us to introduce more conceptual inconsistencies, and in my mind per-site settings should tell you everything about a page that scrolling and clicking through the per-permissions site settings should.

In fact, it was obvious to me that we would do this, but I filed this bug because I realized it's probably not obvious to everyone. :-/

I agree it should be done, but I disagree that it should block anything.

The dialog screenshotted is a pretty rare permission bubble. You only see this if a site calls registerProtocolHandler with a user gesture. Typically sites call registerProtocolHandle - e.g. that is what gmail / inbox / calendar do. If rph is called that way, a page action is used instead.

raymes@ had an interesting idea today, that we should just remove the permission bubble version of this as it is used so infrequently. I think this is worth exploring too (but it doesn't mean site details shouldn't show handlers - it definitely should).