You can run this application even on a file:/// url.

However, the existing SEMPO USSD backend will not let you run this because of built-in browser security measures.

Fortunately, you can get around that by invoking the browser from the command line like this using chromium:

chromium --disable-web-security --user-data-dir=<some bogus empty dir>

Note that you have to kill all active chromium processes first.

Please don't do anything else with that instance of the browser. It's not safe. Really!