At 0:23 of the first period in the Capitals/Flyers game, Washington requested a Coach's Challenge to review whether Dale Weise interfered with goaltender Braden Holtby prior to Jakub Voracek's goal.
After reviewing all available replays and consulting with NHL Hockey Operations staff, the Referee determined that Weise interfered with Holtby before the puck crossed the goal line. According to Rule 78.7, "The standard for overturning the call in the event of a 'GOAL' call on the ice is that the Referee, after reviewing any and all available replays and consulting with the Toronto Video Room, determines that the goal should have been disallowed due to 'Interference on the Goalkeeper,' as described in Rules 69.1, 69.3 and 69.4."
Therefore the original call is overturned - no goal Philadelphia Flyers.
Since the Coach's Challenge resulted in the original call being overturned, the Washington Capitals retain their time-out.