Tony Stark’s keyboard in the MCU involves Mayan glyphs, which was a demand made by Robert Downey Jr., which might’ve to deal with his spiritual beliefs.

There isn’t a straightforward answer when it comes to Robert Downey Jr.’s spirituality, as he once revealed that he has dabbled in everything from Hare Krishna to practicing Catholicism in prison. But while the actor now refers to himself as a Jewish Buddhist, also called JewBu, his experiences and knowledge in all sorts of mysticism did end up playing a part in Iron Man.

Like his character, Downey Jr. had a quite eccentric demand for playing the part that planted the seeds for Marvel’s box-office dominance for years to come. His unique demand involved the Mayan language.
Robert Downey Jr. as Tony Stark

Tony Stark’s Keyboard in Iron Man Uses Mayan Glyphs

Being the eccentric billionaire, Tony Stark wasn’t going to use the normal QWERTY format, and for the technology in the film, Robert Downey Jr. wanted Mayan glyphs to be implemented on the keyboard. While the exact reason behind his demand isn’t known to the public, considering that in the Maya religion, they believed in many gods, which does seem similar to the actor’s spiritual journey, it does make sense.
Iron Man (2008)
To meet the actor’s demand, Visual Designer Ryan Meinerding incorporated those Mayan glyphs along with a unique set of pictograms and created something fitting for Stark. Following its brilliance, the template was then used for every Iron Man entry moving forward, and reflecting on its accurateness, animatic editor Jim Rothwell joked (via MCU: The Reign of Marvel Studios),
“if the ancient Mayan tongue ever became a living language again, Apple would just lift Meinerding’s design.” 
Even though Downey Jr. grew up in a household where religion was secondary despite having Judaism and Catholicism influences present in his childhood, religion did come in handy in his later years.

Robert Downey Jr

Robert Downey Jr. Explained Why He Chose to Practice Catholicism in Prison

During one of his lowest points, he found himself sentenced to prison after missing some court-ordered drug tests related to 1996’s Cocaine possession charge. During his sentence, Catholicism came in handy. Being a  practicing Catholic during his time in prison, Robert Downey Jr. revealed that “there were many times when Catholicism saved my b-tt.” While the Golden Globe-nominated Star never went into explicit details about exactly how Catholicism saved him, he did explain why he chose Catholicism, as this was one of the only two choices.

Further explaining his reason for choosing Catholicism over Presbyterian services, the actor stated,

“Because they just give you more stuff… there’s a whole calendar where this day you read this, the next day you read that. It’s like a call sheet for spirituality.” 
Robert Downey Jr | Iron Man
While the Kiss Kiss Bang Bang Star’s religious beliefs are quite ambiguous from the outside perspective, it does seem the actor is content with the ambiguity.

Iron Man is available to stream on Disney Plus.