[brewdad]

If you are saying that Twitter adjusts the timestamps to the viewer's local time zone, that's not exactly a secret. Or are you accusing Twitter of retroactively changing timestamps to alter the narrative? That would be a bold claim in need of some proof.

[bouncycastle]

They don't, although they can. Say if, the secret service sends them a request in order to protect some higher-up, they would have to comply.