Earlier quoted context omitted.
They're referring to "performance of performance". Not that it's a big deal. I notice problems like this slip into my writing more and more without detection as I get older :/ I don't see the sentence in the Nature paper, though.
Ah-- I've got super bad ADHD so I usually don't even catch things like that. I'm a terrible editor. I wouldn't be surprised if the paper authors were paying attention to this thread, and gave a call to Nature after seeing the parent comment.
Paper: https://www.nature.com/articles/s41586-023-06747-5
Section title: Geometry theorem prover baselines
Second paragraph under that. 3rd sentence from the end of the para.