What does 1 Chronicles 7:15 mean?

Machir took a wife from the Huppites, and his sister's name was Maacah. The second son was named Zelophehad, and Zelophehad only had daughters. 1 Chronicles 7:15 - Modern Text Bible

(This verse explains some family connections in the tribe of Manasseh, showing how the family line continued through both sons and daughters, which was unusual for the time.)