Marco Cimarosti (amongst others, using the same term) wrote:
superscript e *is* the same diacritic that later become "¨"
The term "superscript e" does not aptly describe the situation. Rather, the German a-Umlaut is derived from U+0061 U+0364 (LATIN SMALL CHARACTER A + COMBINING LATIN SMALL LETTER E), cf. <http://www.unicode.org/charts/PDF/U0300.pdf>. Best wishes, Otto Stolz
