sdd:route
sdd:route is dual-role, precedented by sdd:anchor: one term covering both a literal datatype and the predicate whose object carries a value of that type, on the same sdd:Edge at once.
As a datatype, sdd:route is a comma-separated list of absolute interior waypoints, each the x y lexical shape of sdd:vector, written "490 260, 560 260"^^sdd:route — coordinates in the edge's authoring frame, the same group/scope frame sdd:parent names. Projection re-expresses these (and the resolved anchor endpoints) into the computed LCA container's frame purely to render the path; the authored literal itself never changes frame.
As a predicate, sdd:route names an edge's own waypoint list of exactly that literal shape, materialized from a route "<x> <y>, …" line (!route when pinned). The renderer draws from-anchor → waypoints → to-anchor, closing with a straight segment at both ends: repositioning either endpoint node re-aims only its closing segment, while the interior waypoints — the sdd:route value itself — never move. This supersedes an earlier relative waypoint-chain form, whose source-anchored geometry dragged the whole path when the source end moved.