Side Board Mystery Part Identification!

Can someone identify the part shown in the last three photos on this page of the instructions.

The thin black metal part extending from the main assembly to the side board.

Given the BOM for the side board includes only two types of brackets, (corner, and front attachment angled bracket)

Is this a part from the core comps? from the rail kit?

Link the the page.

Part I’m talking about is shown in the last 3 pics.

It’s an L shaped bracket. (part number should be listed with the Drag Chain BOM) It’s used to support the drag chain even if you do not have the side board. I have the sideboard and in the original build, I attached the side board, but since my side board was improperly drilled and serves no real useful purpose, I have removed the it. The bracket however is still in place as it supports the Drag Chain. If you can’t find the item with the drag chain hardware, I would suggest contacting customer support.