The UI for QUnit is provided by the QUnit framework itself. Here, you can filter the test cases for the modules. You can even run the test case for just one module. Here, you can see the progress of each test case, and you can drill down to each step of the test case. Internally, Odoo just opens the same URL in Headless Chrome.

Clicking on the Run tours option will display the list of available tours. By clicking on the play button on the list, you can run the tour. Note that when the tour runs via the command-line options, it runs in the rolled-back transaction, so changes made through the tour are rolled back after the tour is successful. However, when the tour runs from the UI, changes made from the tour are not rolled back and stay there, so use this option carefully.