In the show's finale, Jack became the new God. Veritas is Latin for "truth." Fans speculate that is Jack’s secret creation—a pocket universe designed to keep Dean’s consciousness active so that he can keep the "true" narrative of the original 15 seasons from being erased by cosmic entropy.
The file is small (approx 480MB). It does not contain the entire cast. It is not a happy reunion. Fans who have viewed the verified copy describe it as "haunting" and "the saddest 22 minutes of Supernatural ever produced."