Unfortunately, there is no easy way to link to the docs of the `--cc` (or `-c`) flags at http://git-scm.com/docs/git-diff-tree or https://www.kernel.org/pub/software/scm/git/docs/git-diff-tree.html because they are just alongside the other options in the list. You can use the `#_options` anchor, but that will still involve scrolling down a lot to find the specific docs.

I think this is probably why I also first think to do this command via `log` instead of `diff-tree` -- because the options are isolated in a small section that is easier to read (and also because I use `log` a lot and `diff-tree` rarely).