Closes #25910: fix dead and permanently redirected links in the docs. Thanks to SilentGhost for the patch.
diff --git a/Doc/extending/extending.rst b/Doc/extending/extending.rst
index 4b23463..36de32a 100644
--- a/Doc/extending/extending.rst
+++ b/Doc/extending/extending.rst
@@ -27,7 +27,7 @@
avoid writing C extensions and preserve portability to other implementations.
For example, if your use case is calling C library functions or system calls,
you should consider using the :mod:`ctypes` module or the `cffi
- <http://cffi.readthedocs.org>`_ library rather than writing custom C code.
+ <https://cffi.readthedocs.org>`_ library rather than writing custom C code.
These modules let you write Python code to interface with C code and are more
portable between implementations of Python than writing and compiling a C
extension module.