It's one of the core commands of MCDzienny Lava and it allows you to set the lava state as well as skip the round and get to the next map.
List of possible uses:
/setlava next - skips the current round.
/setlava state 1...4 OR /setlava state calm...wild - sets the lava state.
/setlava reloadmaps - reloads the map list.
/setlava reloadprices - reloads the store prices.
/setlava reloadtexts - reloads textdata.
/setlava up - switches between normal lava and lava that goes up as well.
/setlava protection - turns on/off overload protection.