Spin tool in Blender 2.92.0 rotates only around z-axis by default The documentation says that the spin tool will extrude faces along an arc rotating around the axis of the viewport. No matter which axis my viewport is oriented to, and no matter where my 3D-cursor is, my spin tool makes an arc around the z-axis. In order to spin around the x- or y-axes, I have to open the Spin menu and type in a 1 for the axis I want and type in a 0 for the z-axis.
Click outside to use view axis.

Spinning around camera view, undo, then TOP ortho.
There may be some magic to using the gizmo that appears if you click a plus, revealing the default Z axis path, but it is a slippery beast and TBH I have no idea how to control it. (apart from moving the pivot point)  Perhaps someone will add a better answer re this..
So I resort to align the view to axis I wish to spin around, then click outside the gizmo and spin around similarly to rotation.