koru/dom markup facet — the `component` transform, ported from koru/vaxis (vaxis/index.kz:2944) onto the retained-mode DOM target. RULED 2026-08-07 (DOM_GAUNTLET.md, "how Koru writes HTML") — this file builds exactly that spelling: - a tag starting with a CAPITAL letter is ours: it compiles to a call to that component's synthesized event — a real invocation graph in the AST. - any other tag is passed through untouched. Not looked up, not validated, not compared against a table of HTML element names — the compiler stays ignorant of HTML, which is what makes SVG, elements added to HTML later, and third-party custom elements work for free. What one component synthesizes (architecture shared with the vaxis original; only the paint is retained-mode): koru/dom:component(Row) { <tr data-id={{ id:d }}>…</tr> } → event `Row { parent: string, id: i64, … }` — props read off the {{ ident:type }} placeholders (s/d/f/b, as in vaxis) → a |js paint body: clone a module-level <template> holding the STATIC markup, assign the dynamic attrs/text, append the root to document.querySelector(parent). The template is built once at module load — the same clone-and-fill shape the reference's hand-written rowTemplate uses (vanillajs Main.js:7-9); here the compiler writes it. A row goes in AS IT IS PAINTED, one append each. Batching a task's rows into a detached fragment and attaching once — the trick the reference uses by hand — was built, measured, and REVERTED: on a quieted machine it is 1.112x of hand-written against 1.101x without it. See dom/board/timings-2026-08-08/probes/README.md. Markup dialect (the vaxis attribute forms, extended to passthrough tags): attr="lit" static — lives in the template HTML. attr={{ ident:t }} dynamic — a setAttribute at paint, registers a prop. element text static text lives in the template; text containing a placeholder becomes a textContent assignment and must not share its element with child elements. Capital child tags at the TOP LEVEL of the markup become invocations of the child component's event in a synthesized impl flow, parent forwarded, in document order. A capital tag nested INSIDE a lowercase element is refused loudly this rung (the mount-into-a-node story does not exist yet). The paint is a JS-target lowering; compiling a component under any other --lang refuses loudly, naming this file.