Debir; the same mentioned above, Joshua 15:7. The name of Debir before was Kirjath-sepher: this clause seems to be added to distinguish this from the other Debir subdued by Joshua, Joshua 10:38,39.
Related Commentaries of Joshua 15:15
Joshua 15:15
15 And he went up thence to the inhabitants of Debir: and the name of Debir before was Kirjathsepher.