Hi Beehaw people! New here and hope some of you will take interest in this toolkit and accompanying writeup. :3
Set up a framework to fully man-in-the-middle my own browsers' networking and see what they're up to beyond just looking at their DNS queries and encrypted tcp packets. We force the browser to trust our mitmproxy cacert so we can peek inside cleartext traffic and made it conveniently reproducible and extensible.
It has containers for official Firefox, its Debian version, and some other FF derivatives that market a focus on privacy or security. Might add a few more of those or do the chromium family later - if you read the thing and want more then please let us know what you want to see under the lens in a future update!
Tests were run against a basic protocol for each of them and results are aggregated at the end of the post.
Apart from testing browsers themselves it can be useful for putting extensions under the lens. Making a modern browser properly accept a proxy and trust the mitmproxy cert is a lot more obscure and fiddly than it might seem so hopefully this can be helpful in empowering and pushing other people to peek inside what's actually going on inside their own systems without spending hours or days figuring out what actually makes it tick.
Rewritten cross-post. First Thread @ https://discuss.tchncs.de/post/53845514