After you've installed a UWP application, you may want to know where it got installed to. Maybe there's a deployment bug that you're trying to resolve. Maybe it's just because you're curious.
Programmatically, your application can ask for the
Windows.ApplicationModel.Package.Current.InstalledLocation.Path.
From PowerShell, you can say
Get-AppxPackage -Name YourPackageName
and it will print various tidbits about your package,
including its InstallLocation.
Bonus chatter:
If you are retrieving the path programmatically
because you want to reference
content from it,
you don't need to get the path.
You can use the ms-appx protocol to access
your packaged content.
For example
ms-appx:///Relative/Path/To/Content.jpg
references the specified a file relative to your install
directory.
Some components will accept a URI directly,
such as BitmapImage.UriSource.
If you need to convert it to a StorageFile,
you can use
StorageFile.GetFileFromApplicationUriAsync.