So, we need Fiddler with an extension AppContainer Loopback Utility (necessary for “wrapping” the traffic of the UWP applications to Fiddler). You can download the FiddlerSetup.exe installation file from the official site (https://www.telerik.com/download/fiddler).
After installation, run fiddler.exe with administrator privileges. In the window that opens, click the WinConfig button in the navigation pane.
In this list, you need to select the universal applications whose traffic you want to debug with Fiddler. To reduce the amount of parasitic traffic obtained by Fiddler from universal apps, select only Store from the list and press Save Changes.
In the main Fiddler window, you need to clear the current log (Edit → Remove → All Sessions or press Ctrl + X).
Now you need to run the Microsoft Store, find the application, reference to the .appx installation file you want to get, and run the installation (in this example, I’ll try to get a link for an appx file of the Calculator Free app).
Switch to the Fiddler window and monitor the HTTP sessions of the Store application. There are quite a few of them. To find the event of access to the URL with the application file, you can use the session search (Find → type appx →Find sessions).
Fiddler will highlight the URL with the appx keyword in the URL in yellow. In our example, we are interested in the following session: Result: 200, Protocol: HTTP, Host: tlu.dl.delivery.mp.microsoft.com. Copy the received URL to the clipboard by selecting Copy → Just Url from the context menu.
In my example, the URL is as follow http://tlu.dl.delivery.mp.microsoft.com/filestreamingservice/files/33a43453-eae3-4a23-f9d3-5c7b6698b6b4?P2=12345453486&P2=251&P3=2&P4=kfSejp6k0M0ClMqRktgPCyLQJ6ca1dHYUVkjriTPZbE%3dDigitalchemyLLC.CalculatorFree_1.4.0.74_neutral__q7343f88mnb03.Appx
It remains to open the received URL in any browser and save the file with the .appx extension to your local drive. The archive can be downloaded using any Download Manager or with PowerShell (How to download a file over HTTP using Powershell).
Installing the Appx file in Windows 10 / 8.1 This appx file can now be copied to another computer running Windows 10 / Windows Server 2016 / Windows 8.1 and installed offline, bypassing the Windows Store with a simple double click on the appx file.
Some apps have dependencies, and you cannot install them if you don’t meet these dependencies. Before installing the UWP application, you must first install all required packages. The URL list of all the necessary appx applications (dependencies) will also be present in the Fiddler connection log. Download and install these appx files.
You can install the universal Windows application from the appx file using PowerShell prompt:
add-appxpackage –path “C:\Users\root\Downloads\DigitalchemyLLC.CalculatorFree_1.4.0.74_neutral__q7343f88mnb03.Appx”
So, we figured out how to download the appx installation file of any universal Windows 10 / 8.1 application. The main limitations of this method are:
This way you cannot download the previous version of the UWP application from the Windows Store; You can’t download protected or paid Store apps.
https://www.verboon.info/2012/02/managing-windows-8-metro-style-apps-with-dism/
Install an appx package for all users; this package will be installed on all new user profile creations. Useful to install in a base image or scripted to install before first users login.
DISM.EXE /Online /Add-ProvisionedAppxPackage /PackagePath:C:\data\MetroApp01_1.0.0.3_AnyCPU_Debug_Test\MetroApp01_1.0.0.3_AnyCPU_Debug.appx /SkipLicense