ConstA knob is a plain display value in GeometriesModuleConfig, at the path its id names. Not
knobs: beforeLayerConfig, line.layer, the labels' text and transformFeaturesForDisplay,
which take structured, MapLibre or function values; and events.
Setting any lineLabel knob draws the border labels.
Every geometries knob with its kind, description, range or options and, where one value holds everywhere, its default: the module-wide knobs, the fill and border, then the center and border labels. Static data, readable with no map loaded.