Alzrius
The EN World kitten
The fact that Monte Cook's OGL products always put the names of monsters, magic items, abilities, etc. as Product Identity always ticked me off. There was a reason that stuff got the nickname "crippled content" among the community.When it's there, it's usually in a statement on the credits page or thereabouts, along with other legalese. This is often not the same place where the OGL is. But you're right that it's a thing that's often missed – or at least it was in the early days. I don't know if 3PPs in general have gotten better at it.
As an example, here's how the Book of Experimental Might does it:
View attachment 274155
This legal notice is on page 1, and the OGL is on page 84.