You can't browse and install bbPress plugins because the existing bbPress plugins don't work with bbPress 2.0 and there won't be a bbPress plugin repository for the new version because it is a WordPress plugin now.

Any bbPress enhancement plugins are now simply going to be WordPress plugins you install from the main WordPress plugin installer that enhance bbPress.

So you can browse and install bbPress enhancements right now by browsing the WordPress.org plugin repository via the WordPress plugin installer. But there probably isn't any available yet since it's so new.