Calcium-independent membrane-associated phospholipase that catalyzes complete diacylation of phospholipids by hydrolyzing both sn- 1 and sn-2 fatty acyl chains attached to the glycerol backbone (phospholipase B activity) (By similarity). Has dual phospholipase and lysophospholipase activities toward diacylphospholipids. Preferentially cleaves sn-2 ester bonds over sn-1 bonds. Acts as a lipase toward glycerolipid substrates (By similarity). Hydrolyzes fatty acyl chains of diacylglycerols with preference for the sn-2 position and of triacylglycerols with not positional selectivity (By similarity). May also hydrolyze long chain retinyl esters such as retinyl palmitate (By similarity). May contribute to digestion of dietary phospholipids, glycerolipids and retinoids, facilitating lipid absorption at the brush border (By similarity). {ECO:0000250|UniProtKB:O54728, ECO:0000250|UniProtKB:Q05017}. This is the function of Ensembl gene identifier ENSG00000163803 (PLB1, phospholipase B1).