Since v5.2, Samsung Internet supports Samsung DeX, providing a desktop browsing experience. It is recommended to use Responsive Design to ensure that your site works well in larger desktop windows.
If you need to determine whether your site is being viewed in DeX, you can check the user-agent string. Here is an example user-agent string when the browser is in DeX mode:
Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) SamsungBrowser/13.0 Chrome/83.0.4103.106 Safari/537.36
For comparison, here is an example user-agent string for the mobile browser (not in DeX mode):
Mozilla/5.0 (Linux; Android 10; SAMSUNG SM-G988F) AppleWebKit/537.36 (KHTML, like Gecko) SamsungBrowser/13.0 Chrome/83.0.4103.106 Mobile Safari/537.36
The Progressive Web App Indication Badge also applies to Samsung Internet for DeX. Progressive Web Apps can have their own icon in the tray and on the Desktop. They can be launched in a standalone, resizable window, without the URL bar. The same criteria for the badge apply as above.