Other than The Mandalorian debuting Baby Yoda, one of the most viral memes of 2019 in the world of Star Wars was the use of the word "maclunkey," based on the discovery of an update made to Star Wars: A New Hope in which Greedo utters this line, though the Star Wars gaming podcast The Jodo Cast may have uncovered another usage of the word in 2008's Star Wars: The Force Unleashed. Some fans might think this would present a paradox, given that the game predates the addition of maclunkey to A New Hope, but with some fans thinking the word originated in Star Wars: The Phantom Menace in 1999, the precedence of the word's usage may have been established.
As you can see in the video below, it sounds as though a character utters "maclunkey" after receiving a fatal lightsaber blow, similarly to how Greedo said the word immediately before Han Solo shot him in the Mos Eisley Cantina.
Unfortunately, with little information on the history of the word being detailed in an official capacity, fans have been left to speculate about its origins and its meaning.
Greedo and Han Solo's showdown in A New Hope has famously undergone a number of changes over the years. Originally, it appears as though Han shoots Greedo without warning, knowing he had to make the first move to avoid capture. When A New Hope was released as a Special Edition in 1997, George Lucas tweaked the scene to include Greedo shooting first. The DVD release of the films in 2004 saw another update, as both characters fired at the same time.
When A New Hope debuted on Disney+, fans noticed that the scene had once again been modified, featuring the addition of Greedo saying what sounds like "maclunkey." This change was made prior to Lucas selling Lucasfilm to Disney.
After this update went viral, some fans looked to a scene in which Sebulba confronted Anakin Skywalker in The Phantom Menace, which features the podracer uttering a phrase that sounds like "maclunkey." While there has yet to be an official translation of the word, many have argued it is meant to be an intimidating expletive.
This utterance in the game could be an intentional nod to Sebulba, or it could merely be a coincidence.