Recreated-node caret recovery, tolerant caret validation, per-root retained document trees and cursors across tab switches, document warm-up, coalesced structural moves, and hung-provider fast-fail with an 'Application is not responding' announcement.
Structural navigation to a heading whose native text is a single embedded-object placeholder for its child link showed only that placeholder in braille while speech used the expanded title. Braille line reads now expand embedded objects like speech capture, preserving RawText and native offsets; expanded lines carry no cell routes or native selection/attribute dots and only a line-start cursor. Frame assembly strips any remaining placeholders and falls back to displayed text so a placeholder never reaches the display. Regression tests cover placeholder-only, mixed, expanded, assembled, and empty headings plus native linked-heading and Firefox mixed-line braille. Maintainer confirms physical braille and speech agree on YouTube headings.