At r/Seinfeld, MrJonLott writes:
At the Raynham flea market 2 years ago I found a DVD with 80 minutes of previously unseen Seinfeld bloopers. These are different from the official DVD bloopers, which are already on YouTube. This DVD was in a bootleg case with a bootleg design, and a simple unvarnished disc inside. I ripped the footage from the DVD and uploaded it raw to YouTube. Forgive the video quality; the DVD has low-grade video.
The DVD was produced in 2000, which makes me think it's a bootleg of a blooper DVD made for the cast and crew of Seinfeld in 1998 or 1999, to be shared in the days before internet. There is nothing else on the disc.