Ah, Grand Theft Auto 6. The internet isn't short of rumours or nonsense articles spouting half-truths and speculations regarding the supposed next instalment in the franchise, and we normally don't like to contribute to that noise, but this one caught my interest.
Dataminer rollschuh2282 has apparently discovered some interesting files within Red Dead Redemption 2's latest update that may point to a clue that GTA 6 is actually in development. According to a posting on reddit, references have been found within the latest RDR2.exe file that points to a new parachuting function.
According to the post, this functionality isn't anywhere to be found within GTA5.exe, and has been specifically disabled within RDR2.exe, suggesting it's a new core feature of Rockstar's RAGE engine that isn't intended for Red Dead Redemption 2.
One alternative explanation is that the upcoming release of GTA 5 on PS5 could be using the newer version of RAGE seen in Red Dead Redemption 2, although rollschuh2282 argues this isn't likely to be the case, since the data from RDR2 dates back to 2019, before these next-gen ports would have been in development.
According to him, this is all evidenced by the fact "that parachuting is implemented into the core engine itself, which is why there is a setting in the gameconfig to enable parachuting but is set to false. Similar to crouching in [GTA] V."
It's far from a smoking gun, but it's interesting nonetheless. Rockstar has, of course, not confirmed GTA 6 is even in development right now, so treat this entirely as conjecture.