scmJS docs

Kill

True when the player has killed at least, at most or exactly the number of units of the type.

Condition 5 · Kill(Player, Unit, Comparison, Amount);

Argument Takes Stored in the condition
Player a player or group bytes 4–7
Unit a unit type, or one of the unit classes bytes 12–13
Comparison At least, At most or Exactly byte 14
Amount a whole number, 0 to 4,294,967,295 bytes 8–11
Kill("Current Player", "Zerg Zergling", At least, 20);