LSL Wiki : SmileyScripts

ssExecuteCommand(string cmd, integer num, string str, key id)

Sends cmd, num, str, and id to the SmileyScripts file, from there it is sent to the Mainframe Server, and the server processes the command by identifying cmd and uses the associated needed values, like num, str, and id.

SmileyScripts is a system implemented as a No Modify script file, and is used to communicate with the GridCentral Mainframe In-World Server. Various commands exist, but to hide the actual functionality, you execute these commands using a llMessageLinked template..
For example:

ssExecuteCommand(string cmd, key id)
{
    llMessageLinked(LINK_ROOT, 7413, cmd, id);
}

Or another example, only this one is to call a Rank Identification for the GridCentral Adventures game (Work In Progress):

listen(integer channel, string name, key id, string message)
{
    ssExecuteCommand("GetRank_GCadventures",id);
}

The file is now a work in progress, and will be published to the Teen Grid ONLY since i'm on the Teen Grid, and it's Teen Grid compatible only.