eli5: Why do slot machines have „[BAR] as a symbol?

bar bar slot(Pragmatic Play) Slot Review · Title: Barbar · Developer: Pragmatic Play · Reels: 6 · Rows: 5 · Pays: Scatter Pays · RTP: 96.50% · Max Win: 15,000xBar Slot is set on a 5x3 reel grid with five active pays. To win in Bar Slot, all you need to do is up 3+ matching symbols left to rht on a pay.