There were a decent number of easter eggs in Rogue One: A Star Wars Story, but one that I hesitated to include in my roundup was the location of Darth Vader's hideout. It had a striking resemblance to Mustafar — the planet on which Anakin was bested by Obi-Wan in Revenge of the Sith, because Obi-Wan had the high ground or something — but in a galaxy far, far away with a multitude of planets, you can never be too sure.
But now we can say with certainty: Darth Vader does have a humble abode at Mustafar, which is pretty messed up. The revelation is confirmed in the Art of Rogue One book, per Slashfilm, and was also confirmed by Lucasfilm creative executive Pablo Hidalgo when a fan asked about it on Twitter.
Mustafar is the symbolic birthplace of Darth Vader, as it's where the Jedi formerly known as Anakin fights his former Jedi master, Obi Wan. Things, obviously, didn't go as planned — and it seems that the Star Wars canon will stipulate that Vader uses the planet as a home base. In the Art of Rogue One book, screenwriter Gary Whitta says the choice is a "nod to the conflict in him." "At the same time," he adds, "it's also terrifying, and when he emerges with all of his armor, he's Darth Vader."
The good news for Vader: Mustafar doesn't look like it has any sand. That's a pretty big deal — did you know, he doesn't like sand?