The following packets are unused and have no reason to have handlers:

- CI: character information, unused and handled by SC.

- EI: evidence information, unused and handled by LE.

- EM: area and music information, handled by SM, and obsoleted by
  dedicated FA and FM.

- MM: clientside toggle of whether a client is allowed to change music.
  The handler doesn't even do anything beyond acknowledging its
  existence.

- RMC: plays a music track with an offset. Unused in practice, not
  present in AO2 Client.

- ackMS: sent by the server to acknowledge an IC message, a relic from
  AO1.