[Alsa-user] (sys)default? usbstream plugin?

[Peter P. <pet...@fa...>]

Hi list,

I am trying to understand why is there a 'default' PCM device and a
'sysdefault' PCM device on my Debian system? Furthermore, the
libasound2-plugins package installs a usbstream plugin but I can't seem
to find out what it does or why it is needed in the first place.

Thanks for all pointers about these two questions!
cheers, P