From doubleofive’s Star Wars Visual Comparison twitter account:-
https://twitter.com/StarWarsVisComp/status/1138113595722670080
‘In order to add details into the deep shadows present in the original shot, Vader’s face, chest plate, legs, and right arm were added from another source & tracked onto his body for the DVD. (2004)’…
Harmy pointed this out years ago, and I wasn’t sure what to make of it as we thought it was brightening only. Recently someone else pointed it out again with the explanation that they are new pieces. Check out the tweet thread for GIFs.