`backlog-archive.md`

where a closed row goes, with a `where` cell naming what its content became; ships empty, and a repo that has closed nothing deletes it until the first row moves (ADR-051)

Reference

Status. Optional - part of the core profile.
How it arrives. fill-from-repo - scaffold the shell from the standard, then author the body from THIS repo's reality - never blind-copy the example prose (ARCHITECTURE, PRODUCT, specs)
Shipped form. None - this one is written into your repo during alignment, from your repo's own reality.

The rule that requires it

The repo backlog holds intents, each with a definition of done; an item

See it in the spec