Metallophosphoesterase that catalyzes the removal of a side- chain ethanolamine-phosphate (EtNP) from the second mannose of the GPI- anchor protein intermediate (PubMed:19837036, PubMed:29374258). Participates in the glycan remodeling steps of GPI-anchor maturation to allow an efficient transport of GPI-anchor proteins from the endoplasmic reticulum to the Golgi (PubMed:19837036, PubMed:29374258). . This is the function of MPPE1 (metallophosphoesterase 1, ENSG00000154889).