Internal material the employer owns: the platform documentation, recipe and protocol libraries, training records showing how the knowledge is acquired and by how few, development history and investment, and a statement of how many staff worldwide hold it. Assertions in the petition letter carry very little weight on their own.
Let the company's own paperwork make the argument
An adjudicator cannot verify a claim about proprietary knowledge from a narrative, so the file should contain the artefacts that narrative describes. Useful items include the system manual and its revision history, the crop recipe library with dates showing internal development, the calibration and validation procedures, incident and fault records demonstrating the reasoning applied, and training curricula showing the months required to bring a grower to competence. Personnel evidence matters as much: an organizational chart identifying who else holds the knowledge, and an honest number rather than a vague claim of rarity.
Where the platform is licensed outward, include the licence agreements, because they establish that the company treats this as proprietary property with commercial value. Finally, keep the description of Priya's American duties tied to that same material, so the role plainly requires the knowledge the evidence proves she has.