reworded paragraph on specification

peps/pep-0733.rst

@@ -330,10 +330,13 @@ or a new API tier of "blessed" functions
 API Specification and Abstraction
 ---------------------------------
 
-The C API does not have a formal specification, it is described
-semi-formally in the documentation and exposed through C header
-files. This is also true for the limited API and the stable ABI.
-This creates a number of problems.
+The C API does not have a formal specification, it is currently defined
+as whatever the reference implementation (CPython) contains in a
+particular version. The documentation acts as an incomplete description,
+which is not sufficient for verifying the correctness of either the full
+API, the limited API, or the stable ABI. As a result, the C API may
+change significantly between releases without needing a more visible
+specification update, and this leads to a number of problems.
 
 Bindings for languages other than C/C++ must parse C code
 [`Issue 7 <https://github.com/capi-workgroup/problems/issues/7>`__].