The Joker's "Real Name"

With the recent news that the upcoming Joker movie will have his name be "Arthur Fleck", CBR gives a pretty comprehensive article about the history of the last name of his to be introduced by a movie: Jack Napier. I don't have much to add, so I'll just link to it...

https://www.cbr.com/joker-jack-napier-origins/

...but I'll mention a couple minor things.

1. Contrary to the explanation given in the article, the name Jack Napier comes from the word "jackanapes", which is another word for a mischievous person.

2. The first time Joker's name was hinted to be anything resembling Jack Napier was in Legends of the Dark Knight #50 (July 1993).

3. It's important to note, I think, that the only times his actual name is Jack Napier is in alternate realities. The few times it's used in the main DC Universe, it's as an alias.