The marking step of the "Save as a step" gesture (ADR-0005 part (iii), amended 2026-09-07, clause 18E).

18E says the proposed params are the values the author marks, and every value differing from its field's default where they mark none. So the gesture cannot be a single button - there is a choice in it - and it does not need to be more than a list: one checkbox per config field in the selected subtree, a Save, and a Cancel.

What it deliberately does not draw is a name field or a preview. Naming the type is the host's act (15E), and a package that drew a name field would be drawing a decision it cannot make.

It is a presentation module in the sense every other file beside it is: it renders what it is handed and decides nothing. Which rows exist, which boxes are ticked, and what Save does are StatifierBlocks.Editor's.

A mount that registered no on_collapse never opens this tray: the control that opens it is not drawn and the four events the gesture is made of are refused, so the editor holds no open gesture for this component to render (ADR-0005's Note of 2026-09-08, item 1). The data-collapse-save attribute this section carries is the selector that contract is asserted on, and the "Save as a step" control on the card carries it too.