Bug report

Version

Microsoft.FluentUI.AspNetCore.Components 5.0.0-preview.26260.3.

Description

FluentAppBar renders its overflow trigger as a focusable, clickable div with an aria-label, but without an interactive ARIA role:

<div id="appbar-more-f7730221"
     class="fluent-appbar-more-item"
     tabindex="0"
     slot="trigger"
     title="View more apps"
     aria-label="0 hidden items">
</div>

The component source currently renders this element directly as a div and registers FluentKeyCode for it.

axe-core 4.13 reports aria-prohibited-attr (serious): aria-label is not permitted on this roleless generic element. The element also exposes no button semantics despite being keyboard-focusable and activating the overflow popover.

This is distinct from #1864 / #1871, which corrected the AppBar navigation and item roles but did not cover the overflow trigger.

Repro

1. Render a FluentAppBar with enough FluentAppBarItem children to enable its overflow trigger.
2. Inspect .fluent-appbar-more-item after rendering.
3. Run axe-core with WCAG 2.x A/AA rules.

The same violation occurs even when the label says 0 hidden items, because the overflow trigger remains rendered and focusable.

Expected behavior

Render the trigger as a native button where possible, or give the existing element complete button semantics (including role="button" and correct Enter/Space behavior). Its accessible label and expanded/popup state should be exposed on the role-bearing trigger.