This is the inheritance of the tribe of the people of Judah according to their clans.
Joshua 15:20
"This is the inheritance of Judah" is a double entendre. It refers to the geographical boundaries already described, but also refers to the blessing of Caleb to his daughter in the previous verse.
The story of Caleb, Achsah, Othniel, and the springs in v14-19 is a metaphor of God, Israel, Messiah, and the Holy Spirit. Do you see it?