You should note that it is the difference between a parametric (a vector) .vbr brush and a bitmap .gbr brush.
In the default Gimp brushes folder.
1-pixel.vbr and pixel.gbr
No real need to make your own .gbr brush(s), although it can be convenient. That was the way with old versions of Gimp.
In the default Gimp brushes folder.
1-pixel.vbr and pixel.gbr
No real need to make your own .gbr brush(s), although it can be convenient. That was the way with old versions of Gimp.