@alex@tea 港口 just means "port", so it's "port tea".
I'm going to guess it's shorthand for a specific port that is famous for tea shipment. Kind of like how 普洱, a trading town, became the name for a "class" of tea, pu'er, (when it's really a bewildering variety of classes of tea) or how المُخا was a major trading port in Yemen where coffee was famously traded gave us the term "Mocha" as shorthand for coffee.