This is a port of the hg absorb plugin to git.

git absorb will automatically identify which commits are safe to modify,
and which indexed changes belong to each of those commits. It will then
write fixup! commits for each of those changes. You can check its output
manually if you don't trust it, and then fold the fixups into your
feature branch with git's built-in autosquash functionality.

WWW: https://github.com/tummychow/git-absorb