A break nested inside a trap's break — a fix candidate evaluated at a
bounds stop raising its own error — copied the outer trap's site into
its snapshot, which is a caret pointing at an unrelated line under the
inner condition's name. snap_push now consumes the global: each
snapshot owns its copy, a nested entry that set no fresh site gets
none, and the outer break keeps its own. Pinned end to end.
The fields section says why the values are missing once, above the
rows, instead of repeating the sentence per field; a row keeps its own
reason only when it has one (no printer for its type).
strip_rebind and shown_names get direct coverage, including the clean
strip a real frame almost never reaches.