We display fallback (localized) labels via a chip component with the language ISO code that we currently use for the monolingual text component.

The chips are currently visible for things under the contents area and the header/title bar, but we don't show them in other instances like:

• the function definition under the details tab on the function page
• the function implementations and testers tables
• the about widget
• the function explorer widget
• the testers/implementation widget

We designed a proposal to display fallback labels throughout the product, with an accompanying widget for highlighting the missing labels in the user language, see T329103.

As a first iteration, we can implement only the subtle dashed underline for fallback labels (and display the language name via the title attribute on hover), and later evaluate if it's worth it to add the widget too.