One of the documents that Cole sees in close-up during this scene is a page from a book that features an illustration of a Native American man. It's captioned "Matoka warrior." The image, complete with face markings around the eyes, is a dead ringer for the game character Nightwolf, who joined the "Mortal Kombat" universe in "Mortal Kombat 3" from 1995 and has been a recurring character ever since. He was made part of the DLC for the most recent game, "Mortal Kombat 11," and was a protagonist in the expansion "Aftermath" . His fan-created bio says that he does indeed belong to the fictional Makota tribe (at least in "Mortal Kombat 11") and he has some stereotypically Native American traits, including the fact that his main weapon is a tomahawk. He has green magic and lightning magic abilities.
During Sonya's talk, the camera pans to an image of a god in a headdress. This is a reference to another "Mortal Kombat" character, Ko'atal, the former Emperor of Outworld who took over after the death of Shao Kahn and became playable in "Mortal Kombat X." He, too, appears in "Mortal Kombat 11" as both a supporting character in Story Mode and a playable character. He's originally a warrior from Osh-Tekk, who came to be a hero and god to the Mayans after traveling to Earthrealm — which explains his appearance. His headdress is inspired by Huitzilopochtli, the Aztec God of War and the Sun. He has super-strength and the ability to levy beams of solar fire, drawn from the sun, and a weapon called a Macuahuitl.
Sonya's wall contains additional information about other characters who show up in the movie, too, including Cole himself. There's a headline that blares, "Cole Takes Belt: MMA Lightweight Champion." Cole also focuses in on an illustration of an Asian character that flashes onto a memory. It's a foreshadowing image of Scorpion (Hiroyuki Sanada), who is connected to Cole and has a role in the events of the film.
Basically, if you want more clues about the "Mortal Kombat" universe, you'll want keep an eye out for this scene. Even though some of the characters featured didn't make it into the film, fans of the franchise may appreciate these small nods to them.
