For numpy.fft.fftn and numpy.fft.ifftn, individual FFTs over axes are performed in reverse order.

Similarly, for numpy.fft.rfftn, individual FFTs are performed in reverse order.

However, for numpy.fft.irfftn individual FFTs are performed in forward order.
Currently we compute complex-to-complex FFT for axes[0], axes[1], .. axes[-2] and then one final complex-to-real FFT for axes[-1].
Should it be changed to complex-to-complex FFT for axes[-2], axes[-3], .. axes[0] and one final complex-to-real FFT for axes[-1] (still keeping the complex-to-real FFT over last axis)?

In general, order is not important when calculating complex-to-complex FFTs. However, when we pass s and axes parameters (with repeated indices in axes), order can affect the final shape of the array.