Well, that is done.

Essentially, I would like to let you know something right now that I have discovered.

The Desktop App Converter makes converting the basic app easy - sure. However, if you want to make really any modifications like changing the Display Name to support the ++ in the name, or you want to support opening .xml files (or any other file extension) from the “Open With” menu, it gets really complicated really quickly.

Nonetheless, I have successfully packaged Notepad++ as appx. It will let you open any file ( .xml or .php or whatever), and is signed with my personal certificate.

If you want, I could put out instructions, but I warn you they were not easy to accomplish - took me a few hours experimentation, easily. You essentially have to take the package files, then modify the AppxManifest.xml file to support the file extensions you want, then generate a certificate on your computer (different from the ones -Sign makes), then make an Appx using MakeAppx.exe which is added to your System Environment Variables, then Package that AppX and sign it with signtool.exe . Not easy, but I did it.

You might wonder, wasn’t it working before? It was, but you won’t be able to add extensible features to the package without the long list of complicated steps I just mentioned, for doing things like right-clicking an XML and seeing it under the "Open with " menu, or having a list of default-supported extensions. It will work, but many features that would greatly help out would be missing. You won’t be able to, say, double-click a file in File Explorer and have Notepad++ open it, for example. Desktop App Converter does only the basic stuff - it gets harder, quickly.

If you like, perhaps I could just be the community packager for AppX files… I am here to answer any questions on request, and if you want an instruction guide I will write it.