chromium/chrome/browser/resources/ash/settings/main_page_container/page_displayer.html

<style>
  :host {
    /* Do not show outline when focused. */
    outline: none;
  }

  /* When infinite scroll is removed, only active pages should be visible. */
  :host-context(body.revamp-wayfinding-enabled):host(:not([active])) {
    display: none;
  }
</style>
<!-- This element should be focusable (e.g. After this page's respective menu
  item is selected). Set tabindex="-1" so this element is focusable, but not
  reachable via sequential keyboard navigation. -->
<div id="focusHost" tabindex="-1"></div>
<slot></slot>