I already know how to create a custom URL scheme and set its handler using xdg-utils:
xdg-settings set default-url-scheme-handler name handler.desktop
However, the command affects only the current user. Is there any way (preferably using xdg-utils, as portability is my concern) to register
handler.desktop as the application to handle
name URLs for all users on my system (when any user runs
handler.desktop should be called?
Update: For my Ubuntu machine, appending a line into
/usr/share/applications/defaults.list seems to work:
Is this method portable?