Matondo featured in City's Checkatrade Trophy run with the Under-21s and was a regular member of the EDS starting XI.
He joined the Blues from Cardiff City in 2016, having spent most of his life in South Wales.
Though Liverpool-born, the pacey winger represented Wales at youth level and won eight Wales Under-21 caps.
Rabbi won his first senior cap for Wales against Albania in November 2018.
Everybody at Manchester City wishes Rabbi good luck for the future.