This is a test to see how the printer makes corners when printing on high speed. It is larger than most other tests because in order to reach the highest possible speed the printer needs a fair amount of a straight line. The current 1x1x1cm or 2x2x2cm doe not allow this.
So this is a 100x100mm square, where 2 sides are un-interrupted and the other 2 have a 2mm indent every half segment.

The pictures above show what happens when the feed-rate is changed from 100 to 600%, what happens when the part cooling fan is 40% or 100% (lower fan is more gloss)
Different jerk settings and K setting
How the 90 degrees corners are formed with those settings.

With my direct drive Aero exstruder (Clone) I found Jerk-X=5, Jerk-Y=6 and K = 0.05 at 300% speed a good setting, where the corners did not show any bulging and over extruding or gaps. Also the ringing was very minimal.

In order to do this test I changed all the settings manually on the control box in the menu every 1 cm, this gives a good separation and allows for critical comparison between the 5 different sections.

It is advisable to print a skirt of 10 perimeters and zero distance to the square to make sure it holds on the print bed, as it has only 2 perimeters thickness.