This has to be a terribly naive question, but where does the information about a fund "short selling" a stock come from? Is this information just in the wind,

This has to be a terribly naive question, but where does the information about a fund "short selling" a stock come from? Is this information just in the wind, because the fund is talking about their trades in an effort to further drive stock down and improve their buy back cost? Or, are there some kind of disclosures which must be made while they hold this position? What information was WSB community going on?