LPUB Callout Pointer syntax & bending

[Jörg Schwarzländer]

Can someone please explain to me the meaning/syntax of the <intBase> Parameter in the both metas

0 !LPUB CALLOUT POINTER (TOP_LEFT|TOP_RIGHT|BOTTOM_LEFT|BOTTOM_RIGHT) <floatX> <floatY> <intBase>

0 !LPUB CALLOUT POINTER (TOP|BOTTOM|LEFT|RIGHT) <floatLoc> <floatX> <floatY> <intBase>

And in addition: Is there any chance to model a bended arrow/pointer? If so, how?

If I missed some sources bringing light in this, please point me to them.