WTF Scriptlines!

[P44RTHURN4X]

Hello to all here!

I downloaded some custom stories last time. Then I looked at the script files they have (.hps files). I was wondering about this scriptlines:
SetLocalVarInt("Var1", 0);

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void chemical_1(string &in asItem, string &in asEntity)
{
RemoveItem("chemical_1");
PlaySoundAtEntity("", "puzzle_add_chemical.snt", "acidbarrel", 0, false);
AddLocalVarInt("Var1", 1);
func01();
}

void chemical_2(string &in asItem, string &in asEntity)
{
RemoveItem("chemical_2");
PlaySoundAtEntity("", "puzzle_add_chemical.snt", "acidbarrel", 0, false);
AddLocalVarInt("Var1", 1);
func01();
}

void chemical_3(string &in asItem, string &in asEntity)
{
RemoveItem("chemical_3");
PlaySoundAtEntity("", "puzzle_add_chemical.snt", "acidbarrel", 0, false);
AddLocalVarInt("Var1", 1);
func01();
}

void func01()
{
if(GetLocalVarInt("Var1") == 3)
{
AddUseItemCallback("", "jar_1", "acidbarrel", "giveacid", true);
PlaySoundAtEntity("", "quest_completed.snt", "Player", 0, false);
}
}

I didn't saw them in my live yet!! What the **** is "LocalVarInt"???
Please tell me, what effects these scripts have.