This is not a SFW instance. NSFW communities will be tagged, and efforts will be made to keep SFW communities clean, but proceed at your own comfort level.
HTTP headers or headers in general? For the former I suggest Burp Suite to inspect and manipulate headers to see how things change, for the latter tcpdump/wireshark, to supplement your theory reading :)
HTTP headers or headers in general? For the former I suggest Burp Suite to inspect and manipulate headers to see how things change, for the latter tcpdump/wireshark, to supplement your theory reading :)