How do I set national flags as topic tags in Discourse?

Continuing the discussion from :uk: :de: :netherlands: How to create national flags as topic tags? (And whether to have them at all.):

Could you please explain exactly how you’ve defined this within either tags or a custom SVG theme component. I read your meta.discourse* threads and still don’t understand exactly how this works besides:

  • adding flag icons to a custom theme component
  • …how do I add :de: flag as the actual primary German tag?