v2.11 new diff heuristic?

The release notes mention a new heuristic for diff:

* Output from "git diff" can be made easier to read by selecting
which lines are common and which lines are added/deleted
intelligently when the lines before and after the changed section
are the same. A command line option is added to help with the
experiment to find a good heuristics.

However, it lacks information on exactly how to use this new feature. I dug into the git diff documentation here:

https://git-scm.com/docs/git-diff

It mentions a "--compaction-heuristic" option. Is this the new heuristic outlined by the release notes? If not, which is it? Is the compaction heuristic compatible with the histogram diff algorithm? Is there a config option to turn this on all the time? For that matter, is this something I can keep on all the time or is it only useful in certain situations?

There's still so much more about this feature I would like to know.