- evidence: Item part declares `archetype: 'item'` but Item is a display `<li>` container (not selectable). Timeline.ts explicitly documents: "No `archetype: 'item'` — that archetype is for selectable menu/listbox/option rows... A timeline entry is a display `<li>`, structurally unique, so it omits the archetype." Breadcrumb.Item is semantically identical to Timeline.Item.
- impact: Incorrect archetype declaration violates the 2-of-3 rule (archetype field inconsistent with actual DOM semantics). May confuse CSS-side consumers expecting interactive row styling (cursor:pointer, select, hover). Runtime validator should flag this.
- repro: none (static violation)
- proposed-fix: Remove `archetype: 'item'` from the Item part definition (line 50). Item is a display container, not a selectable option.
- verify: [confirmed] CONFIRMED. breadcrumb.ts:48-56 declares the Item part with `archetype: 'item'` (line 50) on a display container `<li>` (`defaultElement: 'li'`, no role, not selectable). The runtime stamps `data-archetype='item'` on the element whenever the morfo sets it (morfo/types.ts:720 'the runtime emits `data-archetype="..."` on the part's DOM element via `partProps`'; README:177 same). That `[data-archetype='item']` selector triggers archetypes.css:139-153 — `cursor: pointer; user-select: none; min-block-size: var(--list-item-height, auto); padding-block: var(--list-item-py, var(--space-1-5))` — PLUS the hover/highlight band at archetypes.css:161-171 (`background-color: var(--color-surface-raised)` painted on the WHOLE `<li>` on hover). breadcrumb.css:36-41 styles `[data-breadcrumb-item]` only with `display:inline-flex; align-items:center; min-inline-size:0` — it does NOT reset cursor/padding-block/hover, so the styling is unmitigated. This is the exact documented bug: Timeline.ts:88-91 ('No `archetype: 'item'` — that archetype is for selectable menu/listbox/option rows (it ships cursor:pointer, user-select:none, internal padding + a hover highlight). A timeline entry is a display `<li>`, structurally unique, so it omits the archetype.'), and Calendar.ts:247-249 / 270-273 + range-calendar.ts:285 repeat the same doctrine for display `<tr>`/`<td>`. Breadcrumb.Item is semantically identical to Timeline.Item. Real visible regression: a breadcrumb `<li>` gets `cursor:pointer`, `padding-block: var(--space-1-5)`, and a surface-raised hover band over the whole crumb row. HIGH is correct per the rubric's 'archetype-pulls-wrong-styling on a real part'. Fix: remove `archetype: 'item'` from breadcrumb.ts:50 (the Item is a display container; the interactive Link inside owns its own affordance).
- covers: Provider label projection and resolution (BREADCRUMB_LANGS); Link.current state mirroring to Item.isCurrent; aria-current conditional emission (true/'page'/'step'); renderSpan conditional tag switching; Ellipsis decorative->interactive semantics via interactive prop; aria-haspopup conditional on interactive; role=presentation conditional on !interactive
- untested: E2E browser interaction (Playwright): full click/focus flow, ARIA tree, CSS targeting; Eidos variant/size responsive resolution (ActiveEidos.resolve); Ellipsis with DropdownMenu composition (documented example in README)
## Style observations (non-blocking)
- Link focus-visible uses canonical --focus-ring-width and --focus-ring-color vars (breadcrumb.css:61-64, 107-109) ✓
- Ellipsis interactive and link hover transitions use canonical --breadcrumb-transition-duration and --breadcrumb-transition-ease (line 52-54, 94-98) ✓
- Recipe declares all semantic spacing (gap-xs/sm/md/lg → var(--space-*)) and sizing (font-size-xs/sm/md/lg, ellipsis-size → var(--control-height-xs)) ✓
- no hardcoded hex colors; all use role aliases (--breadcrumb-color, --breadcrumb-link-color, etc.) ✓