What does Joshua 21:30 mean?

From Gad, they got Ramoth in Gilead (which was also a city of refuge for people who accidentally killed someone), Mahanaim, Heshbon, and Jazer, with the land around them—four towns. Joshua 21:30 - Modern Text Bible

(The towns from Gad included a city of refuge, showing the Levites’ role in providing places of safety and justice.)