Magit squashing http://www.howardism.org/Technical/Emacs/magit-squashing.html
Splitting commits https://stackoverflow.com/questions/1440050/how-to-split-last-commit-into-two-in-git/1440200 https://embeddedartistry.com/blog/2018/2/19/code-cleanup-splitting-up-git-commits-in-the-middle-of-a-branch https://stackoverflow.com/questions/6217156/break-a-previous-commit-into-multiple-commits https://git-scm.com/book/en/v2/Git-Tools-Rewriting-History