Notice the two grooves (depressions, channels, whatever) above and
below the holes that play the notes.  The extra holes are located in
those channels and are connected to a vacuum source.  When the roll is
in the play position, the depressions are now vacuum chambers which
pull the paper towards the tracker bar.

Did it work?  I don't know, however, I am sure there is a patent out
there somewhere.  I have seen this same setup on several other makes of
pianos, so someone probably held a license for its use.

Ed Gaida - Preserving music by punching holes in paper in San Antonio,
Texas, where spring has already _sprung!_