Did an edit change anything?

authoredChanged(before, after) answers whether a completed transition changed what the author wrote:

const next = RenameForm.bundle.update(model, message, undefined)
if (RenameForm.authoredChanged(model, next.model)) scheduleAutosave()

It compares the two Models, not the Message: validation state, search text, the edited subject, and row bookkeeping are not authored content, so a blur, a refused edit, or a repeated value reports false while a changed draft, an added or removed row, or a changed row reports true. Nested rows recurse through their own forms, and a control whose output is written back into the Model composes for the same reason — which is what lets a consumer such as foldkit-cms autosave without knowing the form's Message tags.