/debug shows raw messages. That is what it is designed to do. Raw messages are all messages that are sent between the IRC server and your client, and the debug command shows them exactly as they are being sent to and received from the server.

If you want to see all the messages for a certain channel, you can try code like this:

Code:
on *:TEXT:*:#channel:showraw
on *:ACTION:*:#channel:showraw
on *:NOTICE:*:#channel:showraw
on *:JOIN:#channel:showraw
on *:PART:#channel:showraw
on *:KICK:#channel:showraw
on *:NICK:#channel:showraw
on *:RAWMODE:#channel:showraw
on ^*:QUIT:if ($nick ison #channel) showraw

alias -l showraw {
window @raws
aline -hpi @raws $timestamp $rawmsg
}

(untested)

Change the #channel's to your channel name.

-genius_at_work