sdd:toAnchor
sdd:toAnchor is the border and offset where an sdd:Edge enters the boundary of its sdd:to instance — the mirror of sdd:fromAnchor, an sdd:anchor literal such as "left 50%"^^sdd:anchor.
Because both ends of an edge are anchors rather than fixed points, the connection holds by construction as either node moves (examples decision 9): the renderer recomputes the anchor's absolute position from the node's current sdd:at and sdd:size and closes the path there, after any pinned interior waypoints.