Every landed feed, when asked.
How an engine runs (a worker thread; a test hands its own).
Runs one engine in a worker thread.
The engine's name.
Its input.
The terms of the settle.
Told how far it has come, 0..1.
Every node's place.
How many layouts were laid out.
Lays out, once, every layout the session does not keep yet — DATA last, after the facts sweep settles, and afresh, since its hubs are the facts. One pass at a time; a failed layout is left for surfaces to settle.