Status
Pre-alpha, but no longer a plan. What works today: open a project, write in source or preview mode, format from a bar that follows the selection or from the ribbon, set the text plain, in a centred column or on the declared sheet, follow the outline and the citations, cite from Zotero by dragging a source or a highlight in, keep the task list in Todoist, compile, and read the PDF beside the source with SyncTeX both ways. Six plugins ship with it, each its own repository and each written against the same public API anybody else would use.
What is not there yet: a new-project wizard, loading a plugin from a directory while developing it, and the Better BibTeX citation-key tier. There are no released binaries — building from source is the only way to run it.
The decision records describe the whole design, including the parts not yet written; they are a plan as much as a history.
Why the decisions are published
A plugin author asking why is the API shaped like this should be able to read the answer rather than guess. So the reasoning is part of the documentation, not an internal artefact — including the decisions that turned out to be wrong and were superseded, and the measurements that contradicted our own estimates.