Colin Trevorrow's Star Wars 9 script offers an opportunity to resolve one of the biggest Star Wars plot holes involving Leia Organa (Carrie Fisher). The original director hired to helm the third film from the sequel trilogy, Trevorrow exited the project before production even came close to starting, with J.J. Abrams coming in to take over. The result was The Rise of Skywalker, which effectively concluded the Skywalker Saga last December. However, it didn't take long before Trevorrow's script, dubbed Duel of the Fates, emerged online, giving fans an idea of how the "threequel" could've panned out.
Production for Star Wars 9 was met with hurdles, but nothing as big as the tragic and untimely death of Fisher, whose Leia was supposed to be the main focus of the film. She was front and center in the newly-emerged full script for Trevorrow's Duel of the Fates, which even offered a way to resolve one of the character's glaring plot points contradictions. During her conversation with Luke (Mark Hamill) in Return of the Jedi, after they discovered they were twins, Leia told her brother that she remembered their mother Padme Amidala (Natalie Portman). However, this doesn't line up with the reveal in Revenge of the Sith that the queen of Naboo died in childbirth.
In Trevorrow's Star Wars 9 treatment, R2-D2 gets hit from a canon blast, sending him flying during one of the film's intended action set piece. Towards the end of the script, as the droid is being mended by a repair droid inside Leia's quarters, Leia picks up the injured droid's still-intact memory drive and inserts it back into him. Soon after, R2-D2 comes to life, sifting through his extensive memory and filing them in chronological order. He simultaneously projects the data while doing this, allowing Leia to watch some of the most important moments in Star Wars history that the droid has witnessed. It includes a flurry of nostalgic shots from the original trilogy, like Obi-Wan Kenobi (Sir Alec Guinness) giving Luke Anakin Skywalker's lightsaber, Yoda lifting his X-Wing on Dagobah, as well as Han Solo (Harrison Ford) and Leia's moment outside of the bunker in Endor.
While the script only names moments from Star Wars' first three films, it's worth noting that unlike C-3PO, R2-D2's memory is intact, meaning that he has a recollection of everything that happened in the prequels as well. This means that he's the only remaining survivor who has a full recollection of the events of the Skywalker Saga — including the blossoming of love between Padme and Anakin (Hayden Christensen), as well as the former's eventual death while giving birth to the Skywalker twins.
After Star Wars: Episode III - Revenge of the Sith, both droids were handed to Captain Raymus Antilles (Rohan Nichol) onboard the Tantive IV, which was where audiences first encounter them at the start of A New Hope. Given this, the droids were in close proximity to Leia while she was growing up as the Princess of Alderaan; with R2-D2 having extensive data on Padme in his memory bank, it's possible that Leia was able to learn a thing or two about her mother - maybe even what her mother looked like - courtesy of the droid. This would've effectively solved her puzzling line from Return of the Jedi in which Leia claimed that she had seen her mother, despite Padme dying just after her children were born.
Now that the Skywalker Saga is officially wrapped up after Star Wars 9, there's really no pressing need to address this aforementioned plot hole. Even if Trevorrow had stayed and directed the final entry in the trilogy, it's safe to say that the film's story would've been changed drastically to work around Fisher's death. But who knows, maybe Lucasfilm will decide to finally explain this mystery moving forward? In the meantime, it'll remain as one of the continuity issues in the franchise.