A Bold New Enterprise - The Making Of Star Trek: The Motion Picture
https://www.youtube.com/watch?v=2nS3-9y2gZU - from the These Are The Voyages YouTube channel (30 mins long).
Star Trek: The Motion Picture Featurette (1979)
https://www.youtube.com/watch?v=aaYLmdun8hs - from the Rengav YouTube channel (10 mins long).
I could really find any info on this, and the YT uploader simply referred to it as “vintage.” I’m assuming its from 1979, same year as the movie. If anyone knows exactly where and when this is from, please let me know so that I can update this post.