[mountainmaster]

For my custom X20 Nylon I specified a neck width of 49 mm at the nut. The width at the 14th fret was increased by the same amount: 61.3 mm.

So as others have mentioned it must be an Emerald design thing. It does help with legato technique up high on the neck, where the high E string can accidentally slip past the fret due to lower tension in the middle of the string.