A 4x4 matrix that is applied to 3d coordinates for perspective. One can instead provide a real number $p$, which is equivalent to placing the screen centered at $z=0$ and the viewer at $(0,0,p)$. Only has an effect if in the outermost GraphicsObject.
The object Perspective is a symbol.
The source of this document is in /build/reproducible-path/macaulay2-1.25.06+ds/M2/Macaulay2/packages/VectorGraphics.m2:1875:0.