I think about eg the "using" section at the top of a .cs file where order doesn't matter and it's common for folks to use the "Remove and Sort Usings" feature in VS.. if that were modeled as a set then diffs would consist only of added/removed items and a re-ordering wouldn't even be representable. And then every other manner of refactor that noises up a PR: renaming stuff, moving code around, etc. in my fantasies some perfect high-level model would separate everything that matters from everything that doesn't and when viewing PRs or change history we could tick "ignore superficial changes" to cut thru all the noise when looking for something specific

..to my mind such a thing could only be language-specific and the model for C# is probably something similar to Roslyn's interior (it keeps "trivia" nodes separate but still models the using section as a list for some reason) and having it all in a queryable database would be glorious for change analysis