Problem

[Mostly a note for myself, or whoever may be interested in rummaging into the axisartist codebase...]

axisartist contains relatively sophisticated code (in ExtremeFinderCycle) to handle angular coordinates, where the tick at 360° (for example) would directly overlap with the tick at 0°; see e.g.https://matplotlib.org/stable/gallery/axisartist/demo_floating_axis.html.
On the other hand, it seems that this functionality is not available for floating_axes; see e.g.https://github.com/matplotlib/matplotlib/blob/master/lib/mpl_toolkits/tests/baseline_images/test_axisartist_floating_axes/curvelinear3.png where the tick at 360° is just overstruck over the tick at 0°.

Proposed Solution

Let floating_axes use some variant of ExtremeFinderCycle.

Additional context and prior art