You have installed a custom theme for your website, and you notice that the theme...

In Drupal 10 and Drupal 11, favicon settings are managed at the theme level , not through general site configuration. The official Drupal theming documentation explains that each theme has its own configurable settings, including the ability to upload or replace the site’s favicon.

To change the favicon, you navigate to Appearance → Settings (or specifically the active theme’s settings page), where you will find an option to upload a custom favicon or use the default. This allows you to replace the default Drupal icon (Druplicon) with your organization’s icon.

Option A is incorrect because the Site branding block controls elements like the logo and site name, not the favicon. Option C is incorrect because Basic Site Settings does not manage favicon configuration in modern Drupal versions. Option D is unnecessary and incorrect, as CSS is not used to change favicons.

Therefore, the correct and documented method is to update the favicon through the theme settings in the Appearance section , making option B correct.