New (to me) sewing table

This fascinating sewing box has just come to live with me- but also comes with a few mysteries.
The box stands about 2' 6" tall and is about 1' square, made sometime in the 20th century but I'm not sure when. I've never seen a cabinet like it.

The top opens up to give access to a box for storing sewing in but also has a flap which comes down. In this space there are the supports and spaces for storing something- possibly knitting needles but there are only spaces for 7 pairs. Any Ideas?

Also, at the back of the cabinet there is a small door with a curious slit in the top edge. The slot is about 2"deep and has two wooden knobs at the base- these knobs screw into each other and are hollow. When the knobs are removed the opening seems to be lined with a metal tube.

The compartment is possibly an area where a ball of yarn could be placed- the end of the yarn run out through the slot and, with the ball contained within the cabinet knitting can proceed without the ball whizzing round the floor. Any other ideas? knowledge?

The drawers are all hinged at the right hand side and swivel out- the top drawer has indentations for scissors and also an area to hold something that was about 4" by 2" and 5/16" deep. Not sure what would have been there?