So I was reading wikipedia and discovered this

“1980: In May, The Empire Strikes Back was theatrically released.[2] After its initial opening, but before its wide release, George Lucas extended the end sequence.[4] A 70 mm print of the film differed from the more widely distributed 35 mm print in takes of dialogue, visual and sound effects, shot choices, and transitions between shots;[5] none of these changes appeared in later releases, with exception of one dialogue change.[6]”

I can’t seem to find any other information about the 2 different versions so I was wondering if anyone had a list or if someone knows where I can find the preservations for each version?