I've been working on a UI extension and didn't find any way to configure an icon for it. It's not a big problem, but label looks a little bit out of place in the side menu (see Extension 1 on the screenshot):

After some source code investigation, I discovered that menu icons are configured via static map:

So it doesn't look like there is a way to extend it.

It would be nice to have an ability to provide an icon in SBA extension config.

My suggestion is to be able able to either provide it as a full html string:

SBA.use({
  install({viewRegistry}) {
    viewRegistry.addView({
      ...
      icon: '<svg xmlns="http://www.w3.org/2000/svg" class="h-5  mr-3" fill="none" viewBox="0 0 24 24" stroke="currentColor" stroke-width="2"><path stroke-linecap="round" stroke-linejoin="round" d="M12 15v2m-6 4h12a2 2 0 002-2v-6a2 2 0 00-2-2H6a2 2 0 00-2 2v6a2 2 0 002 2zm10-10V7a4 4 0 00-8 0v4h8z"></path></svg>'
    });
  }
});

Or just an svg path for more safety and control on the SBA side:

SBA.use({
  install({viewRegistry}) {
    viewRegistry.addView({
      ...
      icon: 'M12 15v2m-6 4h12a2 2 0 002-2v-6a2 2 0 00-2-2H6a2 2 0 00-2 2v6a2 2 0 002 2zm10-10V7a4 4 0 00-8 0v4h8z'
    });
  }
});

Please let me know if you need more details.