A plotly.js sunburst trace auto-detected by MAIDR. The tree
navigates as a tree, on the arrow keys that already exist: up returns to
the parent, down enters the first child, and left and right walk the
siblings inside one parent. Each node announces its exact share of its
parent — the comparison the rings are drawn to support and the one the
eye estimates worst. A treemap or an icicle
trace with the same attributes reads identically; only the name changes.