Documentation at https://melpa.org/#/macrostep

macrostep is an Emacs minor mode for interactively stepping through the expansion of macros in Emacs Lisp source code. It lets you see exactly what happens at each step of the expansion process by pretty-printing the expanded forms inline in the source buffer, which is temporarily read-only while macro expansions are visible. You can expand and collapse macro forms one step at a time, and evaluate or instrument the expansions for debugging with Edebug as normal.