וּמֶ֥לֶךְ אֵ֛ין בֶּאֱד֖וֹם נִצָּ֥ב מֶֽלֶךְ׃
Damals gab es keinen selbstständigen Herrscher über Edom; ein [judäischer] Statthalter regierte dort.
Rashi
There was no king in Edom. [Beginning with] the time of Dovid, the governor22I.e., the governor that was appointed by the king of Yehudah.—Radak was the king. This was written here because in the days of Yehorom his son who sinned, in his days Edom rebelled and crowned a king for themselves, but in the time of Yehoshofot they were still subordinate to him.