Why the Ubuntu App Developer website is not showing content about development for desktop?
As part of the process of making Ubuntu a truly convergent platform, where the apps that you develop can run on any device or form factor, we've started the process of focusing the content on the App developer site to be about the Ubuntu SDK.
While Quickly will still be available and open to community participation and maintenance, the recommended way to develop apps for Ubuntu is the Ubuntu SDK.
This has been discussed at the last two virtual UDSs and you can track the progress and provide feedback on this blueprint