We allow users to extend the primary sidebar, as well as the footer, by defining markdown as a "part" and teaching the theme to look for that part and add it to the relevant UI space accordingly. In order to allow users to add extensibility to the navbar (e.g., icons or badges) we could add follow the same pattern.

Proposal

If the user configures a navbar_right part, it will be parsed as AST and inserted just after the theme light/dark button (the right-most part of the screen).

A user configures the part like so:

site:
  parts:
    navbar_right: icon-links.md  # Or in-line markdown

And in the file:

# in icon-links.md
![](markdown-badge.svc) | {button}`CTA`

And that file will be parsed and inserted here:

Implementation

This would basically follow exactly what we do with footers and primary sidebar.

Considerations

• This would let users extend different UI parts of their site via the same structure we've already started using for footers etc.
• Plugins that define new roles and directives (or PRs like Add scienceicon renderers #752 ) could be used in these spaces without needing new configuration etc.