An observation that supports a non-natural origin is that the pigment appears only in a small, conspicuous location.
Sometimes you don’t need a rigorous logical, scientific, or mathematical demonstration to reveal evidence of design in nature.
William Dembski offers insightful analysis about how we could go about determining whether the virus was designed.
The most valuable aspect of his case is the stimulus it provides to the question, “If non-human intelligences exist, how would we detect them?”
The evidence seems pretty light, at least compared to what we normally expect for a design inference.