iftop | display bandwidth usage on an interface

Sometimes when we install browser extensions on Chrome or Firefox we see many warnings about different permissions that those extensions are using... I know I can monitor all the traffic that happens on my computer in different ways like:

1. Installing a command-line tool like iftop that can monitor the traffic on my computer (on Linux)
2. Installing a tool like Wireshark and also monitor the traffic happening on my computer
3. Check the browser Network functionality when we open its Console

However, all these options are going to monitor the entire traffic of my computer or browser... I'd like to monitor the traffic of a browser extension to see if it's communicating with a server. But it gets very hard to distinguish if a particular traffic is coming from a web extension or not using the tools that I've mentioned... Is there any way of detecting just the traffic of the web extension that I've selected? My first guess would be something like a command that I can use on the browser console to monitor the extension... Is there such a thing?

I see a lot of trust issues when a browser extension asks for a lot of permissions. I think it'd be a lot easier to handle this if I could monitor specific web extensions traffic during the day and check if it's communicating with a server or not... Let's say there's a web extension asking the following permissions: