[Csnd-dev] about m and z variables

in Engine/entry.c is written:
    m       begins an indef list of iargs (any count)
    z       begins indef list of kargs (any count)

i was today looking at the OENTRY of event and event_i which are:
   { "event", S(LINEVENT),0,        "",     "Skz",  NULL, event_opcode, 
NULL   }
   { "event_i", S(LINEVENT),0,     "",     "Sim",  event_opcode_i, NULL, 
NULL, NULL, 2  }

why was event_i accepting ("e",1) as arguments, but not event?
both argument list look the same: Skz and Sim.
is "any count" different for m and z (can be zero for m, but not for z)?

thanks -
	joachim