I’ve got the Vapcell 5900mAh (violet wrap) but not the Vapcell 5500mAh (red wrap). I also have the Shockli 5500mAh.

Doing capacity testing and IR resistance testing (YR1030 IR tester), I would say they are the exact same cell (also tried weighing them with a small digital weighing scale with 0.1gam resolution and they weigh very similar)

So I would add that the Vapcell 5900mAh (violet wrap) is also the same cell as the Shockli 5500mAh, and thus likely the same PLB-55 cell internally.