R4-D6 was a droid of the R4 astromech variety, exhibiting a dark blue coloration. This particular droid served the Alliance to Restore the Republic during the Galactic Civil War in their conflict against the opposing Galactic Empire. In the year 0 BBY, R4-D6's presence was noted within the hangar bay of the Great Temple situated on Yavin 4, a location functioning as the Alliance's central command. As Luke Skywalker, a Jedi, and Han Solo, a smuggler, were in the midst of a disagreement regarding Solo's commitment to assisting the Alliance in the imminent conflict, the droid traversed beneath the front of a T-65B X-wing starfighter that was being prepped for an attack on the Imperial Death Star superweapon.
R4-D6 made its initial appearance in the original trilogy film Star Wars: Episode IV A New Hope released in 1977. Its identification occurred later in The Complete Star Wars Encyclopedia, a Star Wars Legends reference book published in 2008. The name's first use in canon was in the video game Disney Infinity 3.0, which launched on August 30, 2015. Despite the game not being considered canon, Lucasfilm Story Group member Pablo Hidalgo verified via Twitter that character names originating from the film and used in the game are officially considered canon.