I've been building a system called Nexus for the past few months. It's a personal data platform: 54 data sources, 250+ tables, 358,000 knowledge graph facts, all running in Postgres 16 on a home server. It ingests everything from iMessage to Gmail to Apple Photos to Spotify to HealthKit. The goal is biographical intelligence: a queryable model of my own life. A few weeks ago, while wiring up some of the Apple-specific data sources, I cracked open the local databases that Apple maintains on macOS. What I found was... familiar. What Apple stores locally Apple maintains several overlapping SQLite databases on your Mac. The digital forensics community has mapped these fairly well, even though Apple barely documents them publicly.…