Roadmap plans

Roadmap by version

Each planned version has its own branch and its own plan.

One branch per planned version, named release/<version> (for example release/0.5.1).
The branch starts with one document, roadmap/<version>.md, that outlines everything planned for that version. It is the first commit on the branch.
Items move into the document from the backlog. An item has one line of what and why, a one-line acceptance test, and a size when there is an estimate. Items that fit no planned version wait under "Later" in the nearest plan.
Work for the version lands on its branch. The document is edited as scope changes, so it always matches what the version will ship.
When the version ships, its branch merges to main and the branch is deleted. The document stays in roadmap/ as the record of what the version set out to do.

The line-by-line list of what each release contains is in docs/roadmap.md. The plans here are the detail behind it.