[enmyj]

They have used an umlaut on the second repeated vowel in a word for as long as I've been reading. I can't find a link but I believe that's part of their style guide

[mathgradthrow]

Is this an april fools joke?

[slater]

It's not. They've always done it.

[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-...