Can you clarify the indentation logic behind prettifier?

[NightMachinery]

I have asked about the issue here: https://stackoverflow.com/questions/49499245/what-are-the-rules-behind-the-typical-indenting-conventions-of-lisp?noredirect=1#comment86002619_49499245

Here is a screenshot of the question:

[noctuid]

That's how if indentation works in elisp. It's because if can have multiple else forms in elisp unlike in common lisp (the difference in indentation is meant to distinguish the else forms).