Explain the last move

Both players have 38 minutes on the clock and a draw was agreed, even though White just hung his rook?

lichess.org/broadcast/20th-sants-open-2018-round-7/KFZGgAAd

It's game 5 Heimann vs. Sviridov

source of draw?

what do you mean white hung his rook?

Maybe the DGT-board added one extra move after they agreed to a draw. Maybe because the kings were placed on e4 & e5 to indicate the game ended drawn. Only a wild guess of me.

@Mollus is correct.