That's not what the study is about, nor what the title indicates. It was looking at how Musk's own account (and other right-leaning accounts) relative to left-leaning ones were differentially amplified (using a variety of metrics: view counts, retweet counts, likes) since Musk's endorsement of Trump on July 13th, which was also the day of the attempted assassination of Trump by a registered Republican. However, I just scanned the paper and didn't find it to be too convincing, which is why I said in my post "if it proves to be a robust result." Basically, it looks like they are finding patterns in differential amplification of right-versus-left accounts which they suggest might be algorithmic bias, but I think this claim grasping at straws and there are other explanations, such as the already-right-leaning twitter community got more engaged/empowered due to these two events and thus liked, retweeted, and viewed right-leaning accounts, and especially Musk's.