Hello dew1.
It is where the boot files are created for Windows 7 when it is installed to an unallocated Hard Disk Drive (HDD), one that has never been formatted before; it is not necessary but it does several other very useful functions, one being it adds a link to the "Windows Recovery Console" in the F8 or the "Advanced Boot Options" menu at system startup, like in the snip below.
click to enlarge
