`zipfile`: docs should document what `ZipInfo.date_time` actually is

Documentation

Currently, the documentation for ZipInfo.date_time is:

The time and date of the last modification to the archive member. This is a tuple of six values:
...
Note: The ZIP file format does not support timestamps before 1980.

This should be extended/clarified to define which date/time is meant (which currently is only hinted by the does not support timestamps before 1980.

The ZIP format supports for multiple timestamps:

• there's the last mod file time and last mod file date in the central directory (see chapters 4.3.7 and 4.4.6)
• but also various times (e.g. for NTFS and UNIX) as part of the extra fields (see e.g. chapter 4.5.7).

The latter may e.g. support times before 1980, higher resolutions and time zones.

Right now it seems not strictly defined what .date_time actually returns - from what I can see from the code, it's the one from the central directory - but that could in principle be just an implementation detail and a future version of zipfile could e.g. use the extra fields if present.

Thus it would be nice, if the documentation could specify, whether .date_time is always meant to be the time from the central directory, or whether this could change.

Thanks,
Chris.

Linked PRs

• gh-136082
• gh-138076
• gh-138077

Inizia dalla documentazione collegata di zipfile.ZipInfo.date_time ed esamina l’implementazione esistente di zipfile che fornisce questo attributo. Aggiorna la documentazione per indicare quale timestamp ZIP rappresenta e come si rapporta agli altri campi dei timestamp, quindi verifica il testo visualizzato e i controlli della documentazione.