# D17. Backups in a content-addressed version store, not git (6 Oct 2026)

Users never see git: they need to know that backups are regular and that they are safe. Git keeps every version of every binary forever (a deleted 300 MB video stays unless history is rewritten), is not installed on testers' machines, and is heavy to run per project on a server. Elabora keeps versions in `.elabora/backups/` (file contents once, by hash; copy-on-write clones on APFS), taken around AI batches, during activity, on close and as named versions at each release, with a Time Machine-like retention; after 30 days, versions lose the binaries that are neither current nor in a named version, so deleted media leave the backups. The same model maps to object storage on a server. Anyone may still put a course folder in git: `.elabora/` is ignored.
*Revisit if:* teams want branches and merges of whole courses (then a git export, not git as the store).