This version of VLC was originally built and distributed by the M-Audio corperation in combination with their Dolby cards for Mac OS X. It enabled AC3 over SPDIF output for DVDs on these cards. The code to do this was contributed back to VLC and added to the main VLC distribution in post 0.4.3 builds.
This binary is stored here because we don't want it to get lost. It is NOT an official Videolan release. (hence the lack of sourcecode)