Oil Plugs - Simple Question

You have the oil plugs on the gear box and on the final drives that are about 1 1/2 inches wide. In the center is the square 1/2 opening where you put the end of the socket to tighten or loosen it. At the bottom of that square hole on the plugs you see on each corner a tab kind of thing sticking out with jagged edges and they meet in the center forming a diamond shape. Then theres a little space between them and the actual bottom of the plug. Was there a reason it was built like that?

I have taken the liberty to copy a paragraph from vwbroaching.com. Put "www" in front of that for more info.

"Blind broaching refers to the machining of a piece part in which the broaching tool is unable to, because of the design of the part, pass completely through or completely past the part. The broach therefore must cut into a ‘blind’ cavity of some sort. Designing the tooling for, and executing the process of blind broaching is very much an art that is reserved for the most experienced of craftsmen. V W Broaching Service is pleased to perform all types of blind broaching operations, from the most simple ‘punching’ of a shape into a round hole, to more complex forms involving multiple passes using several tools. An example of a blind broaching operation would be the cutting of an internal hexagon into a headless setscrew."

El Toro, no they arent magnetized.