How to figure out if an app is UWP

[wcpusr]

microsoft.com/en-us/store/apps/moovit/9wzdncrfhzk0#app-details

Here is this app. Why can't I download it on my Lumia 930 Windows Phone 8.1 device? Is this a Windows 10 only app? And how am i supposed to know that since there isn't any information in this new stupid store about which OSes the apps support??

 

[7a2eer]

microsoft.com/en-us/store/apps/moovit/9wzdncrfhzk0#app-details

Here is this app. Why can't I download it on my Lumia 930 Windows Phone 8.1 device? Is this a Windows 10 only app? And how am i supposed to know that since there isn't any information in this new stupid store about which OSes the apps support??

Similarly to WP8.1 the app listing will display this icon:

 

[7a2eer]

I checked the app link, it is a mobile only app.
In general there are OS, device, form factor, processor, and or region restrictions.

By scrolling through reviews it would appear this app works on WP8.1. You can contact the developer to see what is going on...