[m.r.f.]

That's a 3rd party app not the native Shield refresh rate option.

This app was developed exclusively for shield.
Not work in mi box or another box.

The app has no advertising. Nvidia certainly ordered it. I don't see anyone making a nonprofit app. 

Lol you are using a non profit app that is kodi itself and think no one would make a nonprofit app.

Lol. But kodi is not unique to a single brand. this app is exclusive to Nvidia shield TV.
What would be the purpose of not working on other brands?