"Extended Versions" is a series of budget priced "live" compilation CDs from Sony/BMG, you can find'em in most stores for around five bucks. There seems to be a disc in this series for just about anybody who's ever recorded for Sony/BMG. The inside of each CD has a note that sez "Be sure to check out other Extended Version titles by..." and lists everybody from 38 Special to Pat Benatar to Motorhead to Foghat, Peter Frampton, Great White, Tesla and the Tubes!!
In most cases these discs are just edited/pared-down versions of previously-released material. The Megadeth one is made up of tracks from the RUDE AWAKENING 2-CD from some years back, and the Anthrax one is taken from the MUSIC OF MASS DESTRUCTION live disc.
...but since I didn't own either RUDE AWAKENING or MUSIC OF MASS DESTRUCTION, and they were cheap, I sez "Ehh, what the hell."
Thanks. I thought they are more "special something".