Does anyone know what is needed to be added to the registry to make an app show up with all its supported file types in the Windows 10 Settings > Apps > Default apps > Set defaults by app list?
This is usually accomplished by using DISM and an .xml file.
To see how this file looks like, use this command:
Dism /Online /Export-DefaultAppAssociations:"C:\DefaultAssociations.xml"
To import, use
You can find more info at the official Microsoft website.