The 3½ minute segment was digitized from an old VHS tape which had been saved by a Back to the Future fan with family connections to the film production at the time the sequels were shot in 1989-1990. To date, the following clip is not available on any other commercial collection, including the recently released 25th Anniversary Trilogy Blu-ray Disc and DVD boxed sets.
There will not be a Back to the Future Part IV nor a remake of the original.
As both Robert Zemeckis and I have stated repeatedly over the years, we have no plans or desires to make another Back to the Future movie -- not a Part 4, nor a remake of Part 1. Nor does Universal or Amblin Entertainment have any such plans. How do we know? Because, per our contracts with these companies, no Back to the Future sequel or remake can even be scripted without discussing it with us first. No such discussions have taken place. We are very proud of the Trilogy as it stands and we want to leave it as is.