There is an image of this cultivar on the Hosta Library. From the photo on the HL website, it appears to be a small size hosta with  green foliage and a very wide creamy white medial (center) variegation. There is only a small amount of green in the leaf so this should be a slow grower. It is a sport of H. 'Jurassic Park' and in July, it bears lavender flowers on very tall scapes. 'Jurassic Sun' is non-registered cultivar was originated by Jan van den Top of the Netherlands.