64-bit TBB linux-x86_64-2.2.31 / FF6 package is actually 32-bit
The new tor-browser-gnu-linux-x86_64-2.2.31-1-alpha-en-US.tar.gz packages the same 32-bit TBB directory tree as the i686 version.
This TBB is actually an i686 installation that has been tar'd up with an inaccurate name. The result is that the apps will not launch due to missing 32-lib libraries that are not typically found in a 64-bit version of Linux.
Trac:
Username: tmpname