Very likely this was not a real job post, but rather the statutory post required for a visa application (H1-B, etc). Zillow HR looked at the current employee's background for a set of skills that is rarely found in one person, to keep the number of qualified outside applicants at zero. "Must be a a senior person with recent hands on experience in this novice tool". What they didn't say is, their exist employee used Prophet in a class unrelated to work.