This is a user's plane modification, that I've not seen before. The plane is a Union No. 7, same size as a Stanley 7. It belonged to my friend's grandfather or great-grandfather, and now belongs to my friend.
3 holes, ahead of the iron, with a little dam in front of them. My guess is that it was for linseed oil, or some other lubricant.
Anybody ever see or hear of this before?