difftastic is great!

This isn't a tool for viewing changes to files or to ASTs. This is a way of being able to generate a single diff file for processing or patching that addresses the kinds of problems we've encountered in over 20 years of building diff parsing tooling and working with over a dozen SCMs with varying levels of completeness or brokenness of bespoke custom diff formats.

It's not an end user tool, but a useful format for tools like code review products to use.