As far as I'm aware, it is a term developed by the company Nutiva, as they have it trademarked, and following is how they describe their product:
"Coconut Manna™ is creamy whole coconut food that will delight people looking for coconut butter, coconut cream, coconut oil butter and coconut body butter."
Being a die-hard coconut lover, I picked some up at Whole Foods and it is, indeed, to die for.
The only thing comparable is the fresh, raw coconut cream I've found at the fantastic shop local to me in Venice, Rawsome. It's the type of thing that is SO good, SO decadent (and yes, SO PALEO), that even eaten as is, alone, it's a delicious treat.
Use it in smoothies, in cooking or, as I mentioned above- have a spoon right outta the jar! Not only will your taste buds thank you, your body will, too!