The declared series type -- 'bar', 'line', 'scatter', …
The series' resolved name.
ECharts invents one ('series 0', with a NUL separator) when the author
supplied none, so a name is only worth emitting when the author wrote it;
see authoredName in the converters.
The series' data list.
Read one of the series' resolved options.
One series of a rendered chart.