This is activated whenever a message is received from a server which is not understood by IRCII. Under normal circumstances this will never happen, however if used in conjunction with /quote, this on function can be used to test new features being added to a server. This will normally be used in conjunction with /alias
IMPORTANT NOTE: ON RAW_IRC can and will seriously impede the operation of the client if not used correctly. If you use ON ^RAW_IRC to suppress a message then the client will ignore it internally as well. Various internal databases will be corrupted and such. Be careful.