Concise Bible Dictionary:
Son of Zephaniah (Zech. 6:14). By comparing verse 14 with Zechariah 6:10 Hen (really Chen) appears to be another name of Josiah. Some treat the word Hen not as a proper name, and translate “for the favor of the son of Zephaniah.”
Potts’ Bible Proper Names:
Free gift; grace; favor; rest:―son of Zephaniah, Zech. 6:14. {Donum gratuitum}