A concept I feel ought to exist, but doesn't exist, in software development is the "diff diff". In other words, if there are two separate patches performing a similar function, I want to see the difference between those two patches. I've been thinking about this for years but I don't think I've ever seen it and I don't even know what word to use to describe it.
You could apply both patches and compare the results, but this is high-friction and doesn't work if the patches have different roots.
