question: private static boolean needsSkylightUpdate ( FastCubeBlockAccess access , MutableBlockPos pos ) { if ( access . getBlockLightOpacity ( pos ) >= 15 ) { return false ; } int computedLight = access . computeLightValue ( pos ) ; for ( EnumFacing facing : EnumFacing . values ( ) ) { pos . move ( facing ) ; int currentLight = access . getLightFor ( EnumSkyBlock . SKY , pos ) ; int currentOpacity = Math . max ( 1 , access . getBlockLightOpacity ( pos ) ) ; pos . move ( facing . getOpposite ( ) ) ; if ( computedLight == currentLight - currentOpacity ) { return true ; } } return false ; }
target:  Determines if the block at the given position requires a skylight update.