What does Jeremiah 52:1 mean?

Zedekiah was twenty-one years old when he became king, and he ruled in Jerusalem for eleven years. His mother was Hamutal, daughter of Jeremiah from Libnah. Jeremiah 52:1 - Modern Text Bible

(Zedekiah, the last king of Judah, starts his reign at twenty-one. His mother’s background is noted, connecting him to his family line.)