[IG_Semmelweiss]

Curious since I don't know about this topic:

Is this sort of packet sniffing (to cheat) far more difficult (impossible?) for browser-based games ?

Assume of course a modern browser fairly standard use of the browser itself

[tga_d]

I would suspect "modern" has a lot more impact than "browser" (notably, aside from more developer awareness of cheating, I would suspect TLS is far more common now, though that can of course be worked around when you control the client). Browser traffic isn't any different from any other type of traffic, the standard packet sniffing tools (tcpdump, wireshark, mitmproxy, etc.) work just fine.