What does 2 Samuel 21:8 mean?

Instead, he handed over Armoni and another Mephibosheth, both sons of Saul's concubine Rizpah, and five sons of Merab, Saul's daughter, whom she had with Adriel of Meholah. 2 Samuel 21:8 - Modern Text Bible

(David selects other descendants of Saul, not Jonathan's line, to fulfill the Gibeonites' request.)