The origin with the deleted record taken out of its chain.
Wherever a link in the chain is the deleted record, it is replaced by that record's own
origin (sourceParentOrigin), so "back" skips the record that no longer exists and lands
where the user came from before it. Returns undefined when nothing is left, and the
SAME object when the chain never mentions the record, so callers can tell "unchanged".
The origin with the deleted record taken out of its chain.
Wherever a link in the chain is the deleted record, it is replaced by that record's own origin (
sourceParentOrigin), so "back" skips the record that no longer exists and lands where the user came from before it. Returnsundefinedwhen nothing is left, and the SAME object when the chain never mentions the record, so callers can tell "unchanged".