I have been away for a while. I am not certain that I ever understood forgot. I see that Single-Supply ICSP Programming allows for the elimination of the 13v supply. So that field programming can be more easily done in the field.

Does the PicKit2 generate the 13v? If so I assume it would generate it when the program is downloaded into the PickKit and it is later used to program a device?

 

The PICkit2/3 have a voltage multiplier on the VPP pin, usually between 8-13VDC.