Final answer:
The claim about the universality of gravity not supported by evidence might concern gravity's behavior in other universes or under untested conditions, as current scientific understanding and evidence only apply to our observable universe.
Step-by-step explanation:
Claims about the universality of gravity not supported by evidence might refer to concepts that extend beyond our observable universe or to theories that haven't been experimentally verified. For instance, while Newton's Law of Universal Gravitation has been refined by Einstein's theory of general relativity, it remains an excellent approximation for most situations encountered in classical physics. Einstein's adjustments to Newtonian gravity become significant under intense gravitational fields, such as those near black holes, and also provide explanations for observed anomalies like the precession of Mercury's orbit.
The question of whether gravity operates similarly in hypothetical other universes or under conditions we cannot test is where scientific consensus ends and speculation begins. As such, any claim stating that gravity operates the same in all possible universes is not currently supported by evidence, given our current methodologies and understanding of physics cannot account for or evaluate the properties of other universes.