This filter is found in
The Pixelize filter renders the image using large color blocks. It is very similar to the effect seen on television when obscuring a criminal during trial.
Here you can set the desired width of the oversized pixel.
Here you can set the size of the obscured square.
If the chain is broken, you can set width and height separately. Otherwise, they are linked.
Here you can select the unit of measure for height and width.