Definition: "those who produce history's first draft"

This is an anagram combined with a charade - look for an indicator word that suggests rearranging letters, plus an additional word that gets added to complete the answer.

'Developed' is the anagram indicator - rearrange the letters of 'OWNERS' and then add a short word meaning a meditator's chant or sound.

Answer: NEWSROOM | 'Developed' indicates anagram of OWNERS, plus OM (a mantra used in meditation) = NEWSROOM (journalists who write history's first draft)