What are these std.zh "Draw Styles?"

To quote from std.zh:

Code:

---

//Draw styles. Use with item->DrawStyle
const int DS_NORMAL            = 0;
const int DS_PHANTOM            = 1;
const int DS_CLOAKED            = 2;
const int DS_LINK              = 3;

---

The central two lines lead me to believe that these are used to affect enemy visibility styles, but seeing "item->..." quickly cancels that theory. What is this used for?

And is there any way to affect an individual enemy's visibility via script at the moment?

I did mess around with draw styles before, and yea, the first two work