This is a double quote: ", 0x22, ascii
This is a smart open quote: “, 0x201c, unicode
This is a smart close quote: ”, 0x201d, unicode
By default your keyboard double-quote key produces the ascii double quote mark, and that is what's used for quoting in virtually every programming language.
Word and many email clients will use smart-quotes by default, but they're pretty rare in programming, hence why the "some among us" phrasing calling them out as strange.
That's what the linked repo is referring to by soft quotes, and the command given specifically uses 0x201d above.