Tomlinsky: This game is often cited as a classic example of blockading an isolated d pawn in the Grunfeld.
Practice shows that 13.Qxf3 seems the more accurate recapture, clearing d1 and adding more support to the impending isolani if black adopts the strategy. In this case 13...f5 may be the better method for the task as opposed to 13...c6 as played in the alternate line.
I'm not sure that with 14.Qb3 black has to abandon, or at least re-evaluate, his plan of blockade if not the creation of the isolated d pawn. Or even the reversal of moves in the a4/b3 queen side expansion so as to prevent the knight passing through c4 on it's way to d6. Keene's move order pushes the knight where it wants to be anyway.
It may be that white should exchange twice on d6 at move 19 which would leave the black queen as the blockading piece. This appears less satisfactory for black than as in the game to me leaving an endgame of opposite coloured bishops and perhaps more potential in the position for white.
It's interesting that going through this game with engines none seem to even get a whiff of implementing a strategy such as Uhlmann left to their own devices. They appear to have white ahead by some margin when he is at best equal it seems to me and see equality when strategically white looks completely lost.