●○○○ — Not much; I'm just letting you know about it.
Steps causing the bug to occur:
Fisheye node not working correctly for FOV > 180
More an informational bug ... the documentation for the fisheye node says it is limited to 180 degrees. Do you mean that a fisheye projection in limited to 180 degrees, or that the node is limited to 180 degrees. Because a fisheye projection is certaintly not limited to 180 degrees, indeed it can be applied to any angle up to and past 360 degrees, although after 360 degrees there is a radial wrapping.
To the operation of the fisheye itself, it is far from ideal. I would propose an option to clip to a unit circle or not ... this applies to any angle fisheye. Even 180 is not actually limited to being clipped to the unit circle as in the current node, although that may an implementation limitation, not sure. And it wold be useful to be able to extend the FOV past 180 degrees.