Previously it was an Alpha, this time it's a Beta. It actually installed on my 64bit Ubuntu.

This Labs release of AIR has all features implemented for Linux, except support for DRM and badge installations. Major new features include support for system tray icons, keyboard shortcuts, localization, internationalized input (IME support), filetype registration, SWF and PDF in HTML, multi-monitor support, fullscreen mode, encrypted local storage, support for V4L2 cameras and printing.
When asked about why wasn't DRM implemented yet,

DRM will be implemented before the final release. Whether or not DRM is welcome by Linux users, we're eager to know.
Heh, so naive...