Earlier quoted context omitted.
He searched the printer logs . Presumably when Word sends stuff to the printer, it doesn't bother with all the extraneous garbage it puts in files. Printer communication hasn't changed much in decades.
Still. He’d have to have the same normal.dot, make the same space/tab choices, same fonts, etc. And in a large company, how many ~1 page letters get printed? What are the odds that there is only a single match in the entire company? I take this story similar to the binary coded space story: more likely to be apocryphal and promoted to deter future leakers than true stories about catching them in the past.
Or have a printer at home on stand-by for your leak press releases. If I were Musk, I would have fired him/her not for being a snitch, but for his/her sloppiness and overall carelessness and lack of discipline.