Real-world media literacy for GTA 6 information. Not every fact that's stated confidently is a Rockstar fact.
Signals it's official
Source: rockstargames.com. Source: on-screen text in an official trailer. Source: a quote in a reputable mainstream press outlet from a named Rockstar person.
If it comes from one of these, it's verified.
Signals it's not
Source is an account on Twitter you didn't know existed. Source is a YouTube video that has 'leaked' in the title. Source is a Discord screenshot. Source is 'someone in the industry'.
Consider them unverified until proven otherwise.