Back in 2006, "Jambe Davdar" (he's listed on IMDB but I'm not sure if it's appropriate to state here) put together this sort of documentary on one of his favorite childhood films, one of the best films of all time, The Empire Strikes Back. I wrote up a full review of how this departs from a traditional doc here: https://letterboxd.com/nottheacademy/film/building-empire-a-filmumentary/
But basically the way this works is that you're watching the old ESB, and then the audio will change to a relevant piece of someone having a pithy interview comment, or the video will switch to behind-the-scenes footage of that sequence. The narrative plays as normal, except a bit longer due to those departures.
The quality of these extra sources varies a lot, and some effort seems to have been made to make them not TOO distracting. Overall, if you're a Star Wars fan, this is a great way to rewatch. You'll probably learn something, as the editor has pulled from really a lot of great sources. And if you're only a casual fan, watching this way as a documentary will be more fun than most docs, and will probably make you appreciate the film more.
*Copied from my Star Wars Begins review* In the same vein as Roger Ebert's commentary for Citizen Kane, this is essential viewing for any and all cinephiles, regardless of your view on the film itself. If there was anyone competent on the Star Wars side of Disney, this would be on all official releases of the film.
While not quite the mythical and surreal act of filmmaking serendipity that the original Star Wars was, the story of Empire Strikes Back is just as compelling, due to the unlikelihood of the movie actually turning out to be good. Lots of fascinating BTS footage and facts while you still get to enjoy one of the great popcorn flicks of all time. Essential viewing for any and all Star Wars obsessives.