If I understand correctly, it is what Lowery introduced on their organs in the 70s called AOC (Automatic Organ Computer) and it added the notes/chords played with the left hand to the right hand melody.
Since the 80s all manufactures have incorporated this feature, as well as greatly expanding on it. (Allowing different sounds for the added right hand notes as well as different combinations of notes for the type of music (Big Band Reeds, Open Harmony, Church etc) being played)
So if you change your board you will not have to worry about loosing the feature.
Hope this helps

Bill