HRC endgame - try to prove that the Russians 'colluded' with DJT to tamper with the election. Then they could say the election was invalid and consequently HRC should be president. This was a Hail Mary to try to get HRC into the WH.
However, their plan had some serious flaws. They did not plant enough evidence to show real Russian interference in the election process. All they tried to do was use circumstantial evidence (very tenuous at best) to imply some sort of cooperation between DJT and RUS.