Install a Windows 10 app that is no longer on the Windows Store

I recently purchased a new computer (Windows 10) and am trying to set it up with all the software I like, but without all the accumulated files and cruft.

One feature I made immense use of was a Windows app I found a couple of years ago, called 'Save as...'. Its function was to add an option in the 'Share' menu that allows you to simply save to the filesystem the thing being shared. It exists on my old machine (also Windows 10, upgraded from 8.1) and I use it frequently.

I cannot find it on the Windows Store anymore, however, and I would like to use it on my new Win10 computer as well. So, my question:

Is there some way to install/sideload a Windows Store app, that can no longer be found on the Windows Store, from my old computer to my new one?

Run the store of Windows 10, go to "my library"

and here you see all apps assosiated to your account.

Go though the list and when you see your app, click on the download button at the end.

If you see an Exclamation mark, the app is not available for a reason. Click on it to show more details.

You can also try to use a HTTP Proxy like Fiddler or Charles to try to get the download link and later sideload the APPX file