Kodak dev or Kodak dev, what's the difference?

[Roger Cole]

I don't think that the mysterious additive used in ID-11 Plus was ever revealed publicly. AFAIK, it was otherwise the basic ID-11 (D-76) formula.

I dint think the actual substance was revealed. The fact it was meant to prevent depleting of dissolved silver back onto the image via physical development was. There was a length article about it in Pop Photo.