It is not working on C6. The window was implemented and the packet structure is there but the messages wont appear in the window.
My guess was that it was just a PoC in the initial C6 release and it as actually finalized in a C6 update patch but i don't have the pre-Kamael Interlude patcht to prove it.
If i remember correctly, you target the player and press //snoop and then this player's inbound and outbound chat appears in a chat window.
On the share: Nice, useful piece of code to replace the //snoop functionality that is missing on Interlude. However it is workin on pretty much any other chronicle after that, making it a bit useful.
A couple on things on the code:
General: (ADMIN_COMMANDS[0]) This is not as smart as you think it is because i have to scroll to the top to see what im doing. Either make them constants with reasonable self explanatory name or use the string itself.
Line 127. This whole check is useless.
Other than that, it's fine.