Are you aware of "stable" orig source archives of Debian? IIRC the ones
in debian/pool/main are removed/updated when the debs are updated.
I usually start with that, and if the tarball is regularly removed, it is possible to switch over to https://snapshot.debian.org/ which is stable for any given timestamp (but the downside is that no new releases show up so the latest version check has to look elsewhere).
But I would wait a few days; there is a high chance the official site will come back soon.