[AStonesThrow]

It is not, in fact, an umlaut, but a diaeresis, which has the same shape but a different linguistic purpose.

https://en.wikipedia.org/wiki/Diaeresis_(diacritic)

In fact, the lede paragraph of the Wikipedia article notes its retention by The New Yorker manual of style, despite being considered archaic.

Direct cited source: https://www.newyorker.com/culture/culture-desk/the-curse-of-...