Companion

The case id of an hourly bucket on the day of an offset change before 1970 by part of an hour (Asia/Shanghai's switch from local mean time), for semanticDivergences: a store may document it as a limit.

The case id of a minute bucket on the day of Africa/Monrovia's 1972 change, after it, for semanticDivergences: a store whose own time zone data reads that day's offset otherwise.

Instants around New York's 2025 transitions, in a half-hour zone's hours, and around Lord Howe's, Monrovia's and Shanghai's offset changes.