This is an attack on the Portuguese language. But it may be a culpable attempt, as it may be linguistic misrepresentation of the author.
Built-in is an English term that is often translated as " sausage ". It means that something about what you say is assembled or built into something greater. For example, a cabinet built into a wall, or the power steering of a car.
In computing it is common to find another spelling, builtin , which has the same meaning. In this case, it can also be translated as "shipped", "delivered", "made available", etc. depending on the context.
What Luiz Eduardo Borges meant by the excerpt in question is that there is a numeric type that is shipped with Python - this type is part of the Python implementation. So, if you have the Python interpreter installed, you can already use this type without having to download anything else.
There are separate modules that introduce new mathematical types and operations that are not part of Python. To work with these types, you need to use libraries that are not embedded / delivered along with Python, so these types are not builtin .
TL; DR: This excerpt from Wikipedia :
the built-in type is a data type for which the programming language provides built-in support
In a very free translation:
"An embedded type is a data type for which the programming language is supported without needing anything else."