GOB is an abbreviation for Game OBject. It can be anything you can imagine in a game. That is the idea to give you freedom to conceptualize what your data is how it looks and how it relates.
A GOB is the definition of a piece of game data it is not the specific instances of it.
Example
As an example we might have a Gob called Monster. It would have a name, description, hit points how what kinds of attacks it might do.
As you can see above this is not a monster it is the definition of a monster. We will go into more details what the other configurations above do, for now know that the above describes what information we need to capture a specific monster. We refer to this definition as a GOB.
If you look closely at the attacks property it is of the type GOB so this means it points to another GOB. Additionally this is an array so it points to multiple GOBS. You can see on the right hand side of the view the definition for it where we select what other GOB it will point at and also what color to use when displaying that connection.
So we also create an Attacks GOB as can be seen below.
Summary
Once done we have two defined types of data (GOBS) one for a monster and one for Attacks. Now we need to start creating Monsters and Attacks. More about that is covered in GOB Instances.