It can be, if the knowledge is of the petitioner's product, process or procedures rather than of programming generally, and is beyond what is ordinarily found in the company's workforce or the industry. Authorship of a core component, and knowledge of why it is built the way it is, is the kind of fact that supports the claim.
Compare her against the company's own staff
The useful comparison is internal before it is external. Ask how many people in the organization could do what she does with the frost-risk engine, how long each of them took to reach that point, and what would happen to a client deployment if she were replaced tomorrow. Then compare with the market: could the company hire someone in the United States who already understands the model, or would that person need months of internal training first?
Write the answer in concrete terms, with dates, project histories and the internal documentation she produced, because an adjudicator reading a general statement about seniority has no way to distinguish it from any competent developer's resume. Salary, seniority and years of service are supporting facts, not the argument itself. Hypothetical example: a geospatial analyst alone understands a company's proprietary shoreline-classification method after four years of internal development.
Her manager should identify the training records, code history, and projects that show why that knowledge is unusual within the company. A first review produces a precise knowledge statement and the US task that needs it. The common weakness is substituting general technical competence for evidence about the petitioner's particular process, leaving no way to distinguish the employee from an ordinarily qualified hire.