commit aacc77fbd77640a8f03638216fa09372cc21673d
Author: Jeroen Demeyer <J.Demeyer@UGent.be>
Date:   Wed May 29 20:31:52 2019 +0200

    bpo-36974: implement PEP 590 (GH-13185)
    
    
    Co-authored-by: Jeroen Demeyer <J.Demeyer@UGent.be>
    Co-authored-by: Mark Shannon <mark@hotpy.org>

removed PyTypeObject.tp_print:

diff --git a/Include/cpython/object.h b/Include/cpython/object.h
index ba52a48358..a65aaf6482 100644
--- a/Include/cpython/object.h
+++ b/Include/cpython/object.h
@@ -182,7 +182,7 @@ typedef struct _typeobject {
     /* Methods to implement standard operations */
 
     destructor tp_dealloc;
-    printfunc tp_print;
+    Py_ssize_t tp_vectorcall_offset;
     getattrfunc tp_getattr;
     setattrfunc tp_setattr;
     PyAsyncMethods *tp_as_async; /* formerly known as tp_compare (Python 2)


Would it be possible to just document it in What's New in Python 3.9? Near:
https://docs.python.org/dev/whatsnew/3.9.html#build-and-c-api-changes


For example, this incompatible change broke zbar project:
https://bugzilla.redhat.com/show_bug.cgi?id=1791745