The request as stated is invalid.
'Int' and 'long' are built-in names, not keywords.

The context of the cited sentence is
"If a name is bound in a block, it is a local variable of that block,
unless declared as nonlocal. If a name is bound at the module level, it
is a global variable. (The variables of the module code block are local
and global.) If a variable is used in a code block but not defined
there, it is a free variable."

Built-in names are not defined in the code block.  Therefore, they are
free names (variables).  However, there is NO mention of builtins in
this chapter up to this point*, so I can see how one could miss that.  
* The previous 'identifiers' chapter has only this:
"The special identifier _ is used in the interactive interpreter to
store the result of the last evaluation; it is stored in the builtins
module."

So something like the following could be added:
"Free variables include the names of built-in objects."

where *built-in objects* is linked to that section near the top of the
Library manual.  (The references later in the chapter are to the Lib
manual entry on the builtins module, which pretty much repeats what is
said later in the chapter.)