Did you know you can use the DevTools to intercept network traffic on your operating system? The application to make this work is called Betwixt, and there are builds for Mac, Windows and Linux.
Once you install it and configure your OS to point to the proxy (check the Betwixt documentation for this), the Network Panel you're used to will display the network traffic which it intercepts.
While I've only tested HTTP, in theory you can also do HTTPS traffic which requires some extra steps. The Betwixt HTTPS branch is here.