This is an important position to remember in rook vs pawn endings.
This position generally arises when there is a pawn on g7 which would be promoted on the next move if not captured.
The reason that this is such an important position has to do with transitions.
Take this position for example.
This is the game Comas Fabrego – Piket 1998. Here White has just played 67.Kf5 attacking Black’s rook. The key here is that Black needs to play 67…Re8. This will tactically protect the pawn on f6 as after 68.Kxf6 Kf3 the first white pawn will fall, following shortly by the second.
Instead Black plays 67…Ra6 and White saves the draw by knowing the position we started out with. Please feel free to try to work out the idea yourself as a training exercise.