What's the relationship between GFP and EGFP?

EFGP is a variant of wild-type GFP, with a higher intensity emission when compared to GFP. As its name states, EFGP (Enhanced Green fluorescent protein) is an enhanced, engineered form of GFP. They both also act as internal chromophores, as they both bioluminesce the color green. Both GFP and EGFP do not require any accessory enzymes/substrates, or biochemical material to fluoresce its color. Thus, both are used as reporters of expression in molecular biology.