Optional ReadonlylimitWhat values are legal on EVERY instance of this row — absent when perInstance.
The absence is the load-bearing part. A field whose travel depends on the instance has a
codec-level fallback sitting right there, and publishing it here would hand a booting client
a plausible number for a control whose real travel is a property of the device behind it —
wrong in exactly the way nothing downstream can detect, which is the defect class this whole
door exists to close. Omitted, a client has nothing to bind but the instance's own OPTIONS.
Optional ReadonlyperPresent when this field's travel is a property of the INSTANCE — a preamp's gain span, an EQ
band's Q — so a client must ask OPTIONS at the instance's own URL and may bind nothing here.
Optional ReadonlytaperThe curve, when the row declares one that does not vary by instance.
Optional ReadonlyvaluesThe closed VOCABULARY this field accepts, when its domain is a discrete set rather than a span — the enum's members, as the codec that refuses them holds them.
A menu is a declaration exactly as a travel is: a client that composes its own options can offer one the desk refuses (which reads as a broken control) or miss one the desk added (which reads as a missing feature, and ships a client to fix). Both are the defect class the travel half of this door already closes; a field whose legal values are a list was simply never asked.
Row-wide by construction: the members are fixed when the codec is built, so unlike a travel there is no per-instance case to withhold.
One field's travel BEFORE any instance is named — the desk-wide half of FieldCapability.
capabilities(id)answers for an instance and so needs one: it resolves an address and reads a live station cell. That makes it the wrong door for a client BOOTING, which needs every travel it will draw with before it has drawn anything, and cannot afford a request per (row, instance) — 125 strips over ~30 rows is thousands of round trips for numbers that do not change.So this is the same declaration read at the other cardinality: what the ROW declares, once, regardless of which instance is addressed.