What does Joshua 15:8 mean?

Then it went up through the Valley of Ben-Hinnom, along the southern slope of the Jebusite city (which is Jerusalem), and up to the top of the hill west of the Hinnom Valley, at the northern end of the Valley of Rephaim. Joshua 15:8 - Modern Text Bible

(The border passes by Jerusalem, which was then called the Jebusite city, and continues along the hills and valleys nearby.)