What does 2 Chronicles 32:32 mean?

Everything else about Hezekiah - his faithful acts and how he built the pool and the tunnel to bring water into the city - is written in the records of Isaiah the prophet and in the book of the kings of Judah and Israel. 2 Chronicles 32:32 - Modern Text Bible

(Hezekiah’s story, including his faith and achievements, is recorded in other historical sources.)