I was a little concerned that the Chain-L shipment label was generated on Monday but the package did not ship (and, apparently, stamps.com gives bogus timestamps to USPS; Monday at 6:30pm Eastern, the USPS website reported the label was created at 9:06pm in New Rochelle, NY — weird), but it finally shipped today.

I…don't understand what this could possibly mean, unless it is tongue-in-cheek?

I'm not an automotive gearhead, but I understand STP sells scores of products (I see 67 on their web page), from fuel additives to motor oil to flat fixers. So I'm not sure which product that means.
But also…looks like?
I'm sure we can make any 2 oils look alike by thinning one to make the viscocity the same and then adding the right dye. But the whole point of this stuff is they have different properties under extended use, different detergent additives (probably not so much on bikes but for sure in cars), dispersants, corrosion inhibitors, polymers for temperature independence, &c.
But I am no tribologist!