In https://reference.opcfoundation.org/v104/Core/docs/Part5/8.2.4/ stands the following:

Starting first line:
"This standard Object is the browse entry point for Object Nodes. Figure 3 illustrates the structure beneath this Node. Only Organizes References are used to relate Objects to the “Objects” standard Object." ...

Fourth line:
... "The intent of the “Objects” Object is that all Objects and Variables that are not used for type definitions or other organizational purposes (e.g. organizing the Views) are accessible through hierarchical References starting from this Node." ...

After that is "Figure 3 - Objects Organization" located - where only Organizes references are used to NodeClass Object Nodes.

And below this figure the sentence: "The “Objects” Object shall not reference any other NodeClasses."

Problem: This leads to the assumption that only Objects below the "Objects" Object are allowed, but the sentence in the fourth line says that Objects and Variables are allowed.

Our understanding: (NodeClass) Object and (NodeClass) Variable are allowed to be referenced with Organizes-References from "Object" Object.

Possible Solution:
Extend the sentence below Figure 3 like the following:
Original : "The “Objects” Object shall not reference any other NodeClasses."
New : "The “Objects” Object shall not reference any other NodeClasses than Object and Variable."