OptionalcolorDefaults to the row's valueColor, then color, then the theme text.
OptionalfieldWhich status-line switch owns this reading. Untagged readings are the
source's own last value, governed by statusLine.lastValueLabel.
OptionallabelDimmed prefix, e.g. O / H / Vol.
One reading on a legend row. Multi-plot sources show one per plot, each in that plot's own color (an MA ribbon's four averages, MACD's three lines) — a single string in a single color cannot say which number is which.