Biofluorescence occurs when a material absorbs ultraviolet light and re-emits it at visible wavelengths. It was known in some marsupials and in New World flying squirrels before it was documented in springhares, in both museum specimens and living animals, as a distinctly patchy pink-to-orange glow rather than an even wash.
The patchiness is the part worth noting. Uniform fluorescence across a coat is easier to explain as an incidental property of the fur; an irregular pattern is harder to dismiss as a by-product. The strongest glow falls on areas that matter in grooming and in interactions between individuals, and both living springhare species show it.
Whether the glow does anything is unknown. It is not established that springhares can see the emitted wavelengths well, nor that any conspecific or predator responds to them, and biofluorescence in mammals may simply be a chemical side effect with no function. The reasonable statement is that a striking property was documented and its purpose, if it has one, has not been demonstrated.