Ensuring safe rollback after Kali Linux apt schema change

Kali Linux uses Debian apt, which updates its package database (sources.list) as part of a schema change, but the rollback of that database is not atomic.

The goal is to guarantee that a system can be returned to its pre‑upgrade state without data loss or broken packages after an apt upgrade that modifies configuration files in /etc.

Constraints include the lack of built‑in rollback for schema migrations, potential conflicts from apt pinning policies, and the need to verify whether the changelog records the schema transaction.

What mechanisms can ensure atomic rollback of the apt schema after an upgrade?
How can apt pinning be configured to prevent unexpected schema changes?
Is there a reliable way to verify that no rollback entry exists in /var/lib/dpkg/updates/ before attempting a rollback?