In Emacs, how do I inspect what has been modified in a buffer (before saving and overwriting the file)?
(In a sense, the requested action is an analog of
git status and
git add -i showing what has been modified, only the comparison should be done between the buffer contents (in Emacs's memory) and the file on disk.)
Sometime, I forget what has been modified in a buffer, and would like to call a command to remind me.