"Documents stolen from the Democratic National Committee and John Podesta, Democratic candidate Hillary Clinton’s campaign manager, were leaked to the media in advance of the election, embarrassing the Clinton campaign. "

I remember the DNC documents showed how the party's internal apparatus (which should have been neutral) was compromised and rigged for Clinton and took active steps to thwart Sanders' candidacy.

I can't recall any coverage of the Podesta documents until I saw the Pizzagate matter being aggressively labelled 'fake' in this and other outlets.  

It's kind of surprising such things could be considered to have made a difference specifically to swing voters in key rustbelt states where the election was actually won or lost.