What is it that you don't understand?
If you don't use () accordingly to give special priority (just like math) mIRC will not (or probably won't) parse the expression the way you expect it to
if (A && B || C)
is undefined, mIRC makes the choice to guess what you mean by actually interpreting it as
if (A && B) || (C)
and in this case it doesn't matter what A and B are as long as C is fine.
it will always pair the conditions from left to right.
If you want it to be A && (B || C) you need to specify it.
