What this map means is that it's the local version of the name. Every name on this map evolved gradually from the Hebrew יוֹחָנָן‎ (Yochanan). The Greeks turned it into Ioannis, then the Romans got it from them and turned it into Iohannes, then in England it became Johannes, and then over time in England it became Johan and then John. Meanwhile, over in Russia, they went from Hebrew Yochanan > Greek Ioannis > Russian Ioanna > Russian Ivan. They sound different now, but they are both "the name of those two important guys in the bible"

In Hungary the name of kings, queens, popes are translated, everyone else stays the same. Non latin script names have a special latinization rules what is very different from English, so it's hard to search for people if you know only their Hungarian name.

In the 19th century and early 20th century they also translated the names of authors and poets, that's whx here everyone calls Jules Verne as Verne Gyula.