difftastic is a structural diff tool that compares files based on their syntax. So for example, if you conditionalize some statement, the diff would only show the addition of one if with its condition instead of showing one line added (the if (condition)) and the line with the statement being removed and re-added (because of indentation changes). In many cases, such structural diffs transport the meaning of a change much better than the typical line-based diffs.
Found on https://www.emacswiki.org/emacs/Magit