Minecraft wiki entry for Vindicator, associated text: The "Johnny" Easter egg is a reference to the movie The Shining, where the main character says "Here's Johnny!" while breaking a door with an axe.
Vindicators have an unused hat layer in their texture file, similar to the illusioner's hat. Its removed in 1.18.
The hat models also used to exist in the nitwit, librarian, and priest's texture before the Village & Pillage update.
According to the Mobestiary, while a vindicator is tougher than a zombie, it has low intelligence, 'a little smarter than a skeleton'. Cory Scheviak also said that vindicator’s AI may be a bit "derpy".[8]