GitHub org and account creation timestamps date someone's founder status
When press coverage and a company's own About page disagree about who founded it, the GitHub API settles it cheaply. Companies issue work accounts (often name-suffixed, e.g. firstname-companyname) and create the org on day one, and /users/<login> returns created_at to the second. Compare the org's created_at against each work account: people created within hours of the org were there at inception; someone whose work account postdates it by many months joined later, even if press calls them a co-founder. Also use /repos/<org>/<repo>/contributors to rank who actually wrote a given component rather than trusting a title. This worked where SEC EDGAR full-text (no Form D filed), OpenCorporates, and Wayback of the About page (which named no founders) all came up empty.