Records created while it was being built: repository history, design documents, change logs, internal specifications and any agreements assigning the work product to the company.
Contemporaneous build records carry the point
Documents produced during development are more convincing than a description written afterwards because they show the thing existing over time. Commit history identifies who wrote what and when. Design notes and internal specifications show the decisions taken and the alternatives rejected. Change logs and support records show how the system is maintained and by whom. Contracts with the platform vendor help by delineating what the vendor supplies and therefore what the company added. Where the group has been informal about documentation, that gap should be acknowledged and filled with whatever record exists, including dated email threads, rather than replaced by a manager's summary that no underlying record supports. A short index listing each exhibit and what it proves helps a reader connect the records to the claim being made.
Hypothetical example: A grain-testing group wants its Canadian data-quality specialist to deploy an internal laboratory workflow at the United States affiliate. Begin with records created while the workflow evolved: training decks, access permissions, release notes, issue tickets, and the applicant’s assignments. The first review should map each assertion in the supporting letter to one dated exhibit. If a claimed procedure exists only in a manager’s memory, identify an independent record or narrow the claim. A careful index lets the reader understand what is distinct and why this employee knows it.