Broderick's head(stock)

I was looking at Chris Broderick's custom Ibanez RGA headstock. Noted the following:

1. The headstock is free from a string retainer. However, there's a sponge-type wedge behind the nut, this is not a replacement contraption but an implement to reduce/prevent string buzz.
2. Do you see any string excess wrapped around the tuner's machine heads? There isn't any. This implies the instrument features a locking device which is a prudent inclusion as the nut is of the non-locking variety. If there is any secondary measure to ensure some tuning consistency, it has to be in this form.