I think this is a case of pangram's attribution being confused. All code examples are AI generated but it places the attribution on the text that surrounds it.
I'm not sure if this author used an LLM, but I think you've misunderstood that paragraph. At worst, the line you're referencing is a tongue-in-check little introduction into a paragraph that describes the top-level differences in approach to serialization that the two libraries take.
deser might also just be deserialize shortened, and I was wondering if it was something focused on deserialization only. As such, I didn’t find a quick little note on the etymology to be a particularly egregious waste of words.
[0] https://facet.rs
[1] https://fasterthanli.me/articles/introducing-facet-reflectio...