Data and backups (Letters)
Everything is in DATA_DIR:
accounts.json: usersowners.json: who owns each claimshared.json: claim index, messagesblobs/: claim files, photos and shared documentsaudit.jsonl: history
The nightly off-site backup (below) copies that folder, and Render takes daily disk snapshots (kept 7 days).
Everything is logged in History, including assignments and reassignments, sign-ins, downloads, uploads, reviews and letters.