How to add "Object specs" to Snapchat Tag?

How should I add “Object specs” values to Snapchat Tag?

This is the documentation:

This is how the Snapchat Tag looks like:

But it is not clear what the object / array should look like.

Not sure if I should create an object called “extinfo” (inside the Custom Data object) and then only have values inside the “extinfo” object (not key:value structure).

Ok, I noticed that the “extinfo” object is just for App related conversions.

So in my case, it is not useful, as I am only working with Web related conversions.