If another browser it could be a setup config option whether clients
can choose to be redirected via tor2web or simply always sent to a
route-insecure address. I will assume for simplicity that all requests
for route-insecure addresses by other browsers simply send to a
route-insecure HTTPS address in the ruleset (if available). I'm going
to also assume that requests for onion addresses for other browsers
simply fail, although if the tor2web option was available and chosen
at the time of setup, then there is another question how to offer this
to the client, perhaps as an HTTPS Everywhere setting.  Comments on
the feasibility, usefulness, design etc. of the tor2web option would
be bonus, but of course I'm most wanting to know about the viability
of the most basic version of things.