...It will work with a bunch of proxies at a time,
dynamically chained or random.
I like to use it with the Tor browser,127.0.0.1:9150
It will display processes and apps connected to The Net,
which is kind of interesting.
I have tested it with Firefox on Windows and it works.
Firefox on Mac doesn't work, but Safari does.
This wasn't really meant for browsers, but for scanning apps.
Works best if the app has the capability of running with a proxy.
It's a bit archaic in this age of VPN's,
but you can actually run both at the same time.