Snapshot of the POP3 sync + storage model, with emphasis on UIDL vs Message-ID and why it matters for lookup. See Database for the general GDBM schema.
• Current Storage — What's in each GDBM file and how it's keyed
• UIDL vs Message-ID — What they are and why it matters
• The Lookup Tension — Why Message-ID lookup currently requires scanning
• BOM Issue — BOM-prefixed stored messages breaking header parsing
• Planned Indexes — Proposed Message-ID index and other improvements