sb_core is the group of Songbird core developers hacking on the code making up the Songbird player and platform.

If you're building add-ons, building webpage integrations, or just building on top of the Songbird platform in general - and NOT hacking in the core code, then you'll be wanting the songbird-dev group instead.

for more info on how to get involved in core Songbird development:

• Getting Started with Songbird Core Player Development

• sb_core, what's in it for you?

• Songbird Bugzilla