[Catalog-sig] PyPI replication project

["Martin v. Löwis"]

> Sorry... this is more speculation than based on actual knowledge, but I
> think there are feasible ways to do these things.

PyPI provides mirrors with a changelog where they can efficiently ask
for a list of packages that have changed since they last synchronized.
This is the recommended way for mirrors to operate; polling the
changelog once every minute is acceptable load for PyPI.

Regards,
Martin