Video of the press conference is here
What they did was basically establish (under oath, with document trail) that the fossil fuel industry executives knew about the damage that burning fossil fuels did, and decided to cover it up, rather than be forthright with people and legislators. They’re now referring this to the justice department to see if prosecution is possible.
They had some inkling that there might be an issue, but the modern consensus (and oil company reaction to it) basically emerged in the late 1970s