.drawio (mxGraph XML) import — the migration on-ramp from draw.io / diagrams.net.
Reads plain <mxGraphModel> XML and the default compressed
<mxfile> save (base64 → raw-deflate → URI-encoded). Vertices, styles,
swimlane containers with real membership, edges with labels, arrow markers, manual
waypoints (applied, not parked), edges that end on a container, and
multi-page files (every page imports; pick one below) all map onto the engine's
own models — and every construct the import drops is named in a warning, never
lost in silence.