<chart:chart> in the object's sub-document, read through the same picture as
the DOCX leg: series values by cell range out of its own local-table, colours
from the series style, bounds from the axis style.
word/charts/chartN.xml → an SVG picture of the frame's size: series from the
producer's numCache, theme accent colours, titles, gridlines and the axis
bounds the file fixes. Bar, line, area, scatter and pie; the rest keep the box.