There are so many clues:

• The knowledge of Ohara is confirmed to be stored in Punk Records. Vegapunk read all the books of Ohara, and did even further research, and it’s very likely that he discovered one of the biggest taboo secrets of the World Government: The existence of Imu.

The taboo knowledge of Ohara is confirmed to be stored in Punk Records.

• The Revolutionary Army learned the truth of Empty Throne from Sabo, which makes you think: What comes next? There are two things that can happen: Either the Revolutionary Army reveals the truth to the world, or it gets revealed now from Egghead. I don’t see a point of the Revolutionary Army learning the truth if the secret won’t get revealed to the world soon.

Sabo revealed everything to the Revolutionary Army.

• We saw Sabo, Dragon, Ivankov, Cobra, and Wapol all learn about the truth in this arc. IMO this indicates this info will become public knowledge very soon and will not stay a secret for much longer.
• Morgans is already listening to what’s happening on Egghead, and waiting for the big reveal.
• Wapol is with Morgans, he’s going to confirm the info to Morgans when it’s revealed.

Morgans is listening, and he already has an eye-witness (Wapol) with him.

• The reason Saturn came to Egghead is not just to control the seraphim or pacifistas. He came to Egghead to do something bigger than just assassinating Vegapunk; something the Five Elders won’t let even Kizaru or Lucci do by themselves: To access Punk Records and erase the truth from them, because whatever information is in there is too sensitive and must only be seen by the Five Elders, nobody else.

Saturn came on a top-secret mission, that only he can perform.

• World-level events are already starting to happen, with the Lulusia incident and the rise of the ocean. This is a buildup for something bid, and not just a side plot with no end result. I think it’s building up for the big reveal. It’s time for the world to see the reason for these big events.

The world has already started to change.

• • With the ongoing battle and the Buster Call, it’s very likely that Punk Records will get damaged and start to malfunction. This could somehow lead to the big leak.
  • Nothing will shock the world more than learning about the existence of Imu.

This is the truth that will shock the world.