The screen annotation renderer keeps each mark's SVG parts as attribute
records and presents the board to a store after every rendered frame; a
view teleports it to the page and hands back the callout text and mark
groups the renderer measures. The tracked-entity fade is measured once
the frame is in the document, removed marks fade out before they leave,
and the styles it injected move to annotations.css.
Sameh Khamis
662f51fdf3