Toshiba's "Recovery Environment" -- What was the idea behind this disk?

I have a Toshiba Satellite A665-S6094 here for which I have just made the system recovery disks. There are three system recovery disks and an additional disk called "Recovery Environment". This "Recovery Environment" is not included if you buy the system recovery DVDs from Toshiba and my little bit of Googling seems to take me to no explanation as to what the idea is behind this disk.

I suspect it is superfluous; but, what was the idea behind including it in the system recovery set in the first place?