ReadonlycodeThree capital letters.
Optional ReadonlyexampleAn index of it, for the refusal that teaches the syntax (@SER3); a kind without one is not shown there.
Optional ReadonlygroupThe kind stands for other rows (a study for its series, a patient for
theirs): a whole listing handed on (a pipe, ${listing}) gives its
other rows, never these, so nothing is taken twice.
ReadonlywordThe kind in words, for a refusal: a series.
A kind of row a listing numbers, as an index writes it:
@SER3is the third series.