Drawer
In order to make room for a larger fridge, the drawer from the lower kitchen cabinet was moved to the closet.
The drawer is mounted under one of the shelves. In order for this to work well, the shelves had to be secured to the internals so that it could not move.
The hardware is for a keyboard slide.
https://www.amazon.ca/dp/B07FLZVK3B?ref=ppx_yo2ov_dt_b_product_details&th=1
Shelves
Shelves have a small lip on them to prevent things from sliding off.
Shelves are secured to the internal rail using screws into the rail and into the shelf.