Interesting. My own approach is just to use a minimal template that doesn’t have a web browser installed at all for qubes in which I don’t want links to open in a web browser.
Well, up to now I did not have a look into minimal template but your approach looks also doable. Nevertheless, the implementation of this simple tool would make it super simple for all without making the manual work one-by-one.
I am absolute sure that all of us forget sometimes the SHIFT+ctrl.+v when we want to copy something to a different AppVM. For me it is the same with links in i.e. a messenger or private AppVMs which you do not fully trust but accidentally you just click instead of ctrl.+c > shift+ctrl.+c > shift+ctrl.+v > ctrl.+v the link.
Needless to say everyone could implement the small tool into her/his Qubes but I think the implementation effort to bring this into standard is small compare to the benefit and security it brings for Qubes users.
Oh wow, I accidentially sent this with a PGP signature and then came here to apologize and edit/remove it. Seems Discourse has automatically taken care of it … which means I don’t have to think about it. Awesome!