gio:app-launch-context-startup-notify-id (context appinfo files)

context -- a g:app-launch-context instance
appinfo -- a g:app-info instance
files -- a list of g:file objects

The string with a startup notification ID for the application, or nil if not supported.

Initiates startup notification for the application and returns the DESKTOP_STARTUP_ID for the launched operation, if supported. Startup notification IDs are defined in the FreeDesktop.Org Startup Notifications standard.