Quoted from this original website :

"This focus calibration chart can help you test the accuracy of your SLR camera's autofocus, and find the right focus micro-adjust setting if your camera has that
feature."

http://www.squit.co.uk/photo/focuschart.html
http://www.squit.co.uk/photo/files/FocusChart.pdf

Ònshape file:
https://cad.onshape.com/documents/59663b4db22fc559186350bb/w/a0901e9fd6231207d4dd03aa/e/a4a2679e48e41d5fd53a1972