Just found about a French MP with a slash in her last name : Emeline K/Bidi. I’ve never seen that before! https://fr.wikipedia.org/wiki/Emeline_K/Bidi
One more concrete example for the "Falsehoods Programmers Believe About Names" article
Apparently this is an abbreviation of the Breton prefix "Ker".
"K/" was a normal breton "letter" like "c’h" until it got forbidden in civil registries 1895, but bretons who settled in Réunion island (colonized it with the French, let’s be real) at that time were able to keep it.
It tends to disappear today as it gets denied to be entered in civil registries. She mentions she had to register her son as "K’Bidi" instead.