This newest "leak" concerns an upcoming apartment and safehouse customization feature, allowing you to play interior decorator and architect with your in-game properties. A relatively unknown YouTuber posted a video about how he allegedly found images and game files dug out of the GTA Online Lowriders source code. Turns out, however, that these were all fabrications, and the files he "found" in the code were actually created by the YouTuber.
In recent weeks, DLC releases for GTA Online have become more and more frequent. As a side effect, the official announcements always happen really close to launch, meaning we probably won't get any official info on upcoming updates until a few days before actual release, or on the day of release itself.
People are determined to find out what the next DLC for GTA Online will contain. Players know to anticipate a few vehicles — as of the 12 cars found by the data miners who uncovered Lowriders, only 6 have been released (or 8, depending on whether or not the Halloween vehicles come from that batch). Lowriders added a fourth purchasable property to the game, allegedly to buff out garage space, but with the attention properties got, it is plausible that apartment customization is in the pipeline.
This leak, however, is definitely a hoax!