Quoted from the FAQ
Third repetition of a position. If any identical position appears three times during a game, then the game can be claimed as a draw. Please note that each repetition must be identical with regards to en passant and castling availability. A draw can only be claimed along with a move that contributes to a repetition. Claiming after the repetition has occurred is not possible, unless the same position can be repeated again on a future move.
Missing from this definition is that the same side must have the move
in all 3 of the occurrences. This is per FIDE rules.
Hopefully the draw claim is implemented correctly on RHP despite the omission in the FAQ.