Comment by pimterry

You can proxy anything, it's just the "intercept the entire system" isn't automated here (because targeted interception is usually preferable).

For system-wide setup, you'll just need to configure that manually - setting your system proxy and trusting the CA certificate. The settings you need are on the Intercept page, in the 'Anything' section. For portable browsers, you may also be able to configure proxy & CA settings within the browser itself, which might be more convenient, depending on your setup.