On https://online-go.com/joseki/63, [4] should be called [D] and given an explanation.
A few moves down the line, at https://online-go.com/joseki/55562, there doesn’t appear to be any meaningful difference between moves [1] and [2], which look like different move orders that coalesce into the same result.
Also, a pedantic point: surely the asterisk citation * should come before the double asterisk ** in the text.
Really, I think the proper convention is for the second citation to be represented by the dagger † and the third one by the diesis (double dagger) ‡