What are these std.zh "Draw Styles?"

[ShadowTiger]

To quote from std.zh:

//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?