Per today's discussion, here's the engineering input for this task (this has also been added to the parent epic):

Codex implementation

At the end of the day, a Breadcrumb component is a way to display a list of links in hierarchical order. The last item should correspond to the current page. The last item does not need to be a link, but all other items must be links.
Our implementation of this component should follow the ARIA Authoring Practices Guide guidelines for "Breadcrumb Pattern".

Open questions

• How much customization should we support here?
  • The Vuetify Breadcrumb component supports a fair amount of user customization by exposing named slots. We should consider doing something similar here; one Breadcrumb pattern may be appropriate for on-wiki usage, while another style might better suit usage on an external site. We should consider adding slots for the following things:
  • First item (aka "home"): Custom display for the first item in the list. Users may want an icon or logo here for example.
  • Breadcrumb items: Similar to how components like Select allow for custom styling of MenuItems via a scoped slot, we may want to allow custom styling of each "Breadcrumb Item" in a similar way. All of these items still need to be link elements per the ARIA guidelines, but the contents of the links could be customized
  • Last item (aka active item) – This may also be a link but perhaps its markup can be similarly customized via a slot
  • Separator – we should provide a default separator element (icon, arrow character, etc) but users may want to override this as well. This item should always have the aria-hidden role so that it is not announced to screen readers.
• What does mobile UX look like – Mobile devices probably won't have room to display a long list of horizontal breadcrumbs, so we may want to hide some of this on phone-sized screens.
• "Breadcrumb groups" – Can breadcrumb elements have dropdowns that contain other elements nested inside? Maybe but this is probably outside the scope of the MVP.