As noted, Chris Jericho interfered in the main event pitting WWE Universal Champion Kevin Owens against Seth Rollins, which you can watch in the video above at the 1:40 mark. Jericho was wearing a Sin Cara mask when he made the attack.
As noted, Jericho and Sin Cara were involved in a scuffle on the tour bus during the recent WWE European tour. Sin Cara was going to be sent home at one point but was instead "exiled" to the SmackDown leg of the tour, even though he never worked a SmackDown live event. On the first RAW in the U.S. after the tour, Sin Cara was not allowed to use the regular locker room for WWE talent and had to change in the "extras" room.
Jericho stated on his podcast that Sin Cara is a great guy who is a good friend of his, and revealed that Cara actually lent him the mask.