How do I use the install package button?
It says the "pysn" thing isn't used by any program :(

It's an upcoming feature of the Curse Client. When the new version will be launched remains to be seen.

I'm really looking forward to this function, it would be cool if you could add a Blizzard Launcherish future, maybe just the possiblity to start WoW from it, also automaticly check for new versions of your addons at startup, and on exit.

you could make a batch file that loads curse and also loads the launcher.