There is also https://meldmerge.org/ which i've used on Linux and Mac before.
e.g. in the CLI you might do something like `git diff commit_a commit_b -- some/path/in/repo` to show the diff from commit_a to commit_b limited to some path
Refer to the "configuration" sections for
https://git-scm.com/docs/git-difftool
https://git-scm.com/docs/git-mergetool
these git documentation pages mention meld (along with many other diff tools).