= sign in a katakana name

I was surprised when I came across this Wikipedia page: アーシュラ・K・ル＝グウィン

Does someone knows what that = sign is? I can see it works as a separator like 「・」 Is it simply an alternative?

Answer

It's a double hyphen, not an equals sign.

One of its uses is when transliterating names that have a hyphen in them. This is to avoid confusion with the extended sound symbol (ー) in Japanese. For example: クロード・レヴィ＝ストロース (Claude Lévi-Strauss)

Another time when the double hyphen is used is when in the original language, there is a stop in the sound. Your example fits this case. アーシュラ・K・ル＝グウィン (Ursula Kroeber Le Guin). In English there's a very obvious stop after Le.

Now you might ask why use the double hyphen instead of ・ (the interpunct). After all, ・ is used way more often in nearly all cases as noted here: 　中黒（・）を用いるのが一般的だが、厳密な規定は無い。. It seems that it mostly depends on whether the text is vertical or horizontal.

For vertical text, ・ is preferred overwhelmingly. For horizontal texts, ゠ can be used instead, although people still generally use ・. Source: The best answer from here