Mangi's

Very common to find many a shops like this in Dar. In such a kiosk, one should expect to get many of the basic groceries a household would need on a regular basis. Items ranging from socks to eggs, drinking water to airtime vouchers can all be found in such shops. They are located mainly in residential areas, usually found in the vicinity of a house/compound. Most of all, why is it always a "Mangi' would be the one owning such a shop?