Breadcrumbs

Breadcrumbs above the page header — where I am and how to get back. In an application without a side menu they carry all the orientation in depth.

When to use it

A detail you can only reach through a list. The top bar says which section you are in, the breadcrumbs say how deep — and without a side menu there is nobody else to carry that second piece.
A path deeper than two crumbs. Section, list, item: only here does the reader have something to lose, and the breadcrumbs give it back.
Going one level up in a way that is not the browser's back button. Someone who arrived from a link has no history — only the breadcrumbs show them the way upwards.

The root page of a section. A single crumb says nothing the header does not say better — so for fewer than two crumbs the component returns null and no trail is drawn at all.
Navigating between siblings — tabs above the content, a view switcher. Breadcrumbs lead upwards, not sideways; steps to the side are IngotTabs.
A replacement for the main menu. Breadcrumbs say where you stand, not where you can go — the application's sections belong to IngotTopNav.

items: readonly IngotCrumb[] — The path from the top down. Fewer than two crumbs render nothing at all.
label: string — A translated aria-label for the navigation. Otherwise a screen reader announces only “navigation”.
testId: string — An anchor for tests. It affects neither appearance nor behaviour.