What is: Kodak B/W Focus Test Negative?

Bought some enlarging equip and the below focus test negative was in the box. I suppose this is used to check the focus on an enlarger's lens? I figure if it was a positive (slide) it would be used to test focus on a slide projector? I have never seen one of these, anyone use one of these, any advice? Do you do a print of it too?

Looks like a cool thing. I haven't seen one before, but it looks like you could use it to test and adjust enlarger alignment, and it could also be used for projectors and duplicators.

Used for setting printers of enlargers

Hi zsas, any chance you still have this negative? Check you PM - thanks!