diff -r 00ca2c8e2506 Doc/whatsnew/3.5.rst
--- a/Doc/whatsnew/3.5.rst	Tue Sep 08 23:45:23 2015 -0700
+++ b/Doc/whatsnew/3.5.rst	Wed Sep 09 02:20:19 2015 -0700
@@ -1007,6 +1007,54 @@
 
 Changes to Python's build process and to the C API include:
 
+* Extension modules now include platform information in their filename on
+  some platforms:
+
+  * On Linux, extension module filenames end with
+    ``.cpython-<major><minor>m-<architecture>-<os>.pyd``:
+
+    * ``<major>`` is the major number of the Python version;
+      for Python 3.5 this is ``3``.
+
+    * ``<minor>`` is the minor number of the Python version;
+      for Python 3.5 this is ``5``.
+
+    * ``<architecture>`` is the hardware architecture the extension module
+      was built to run on. It's most commonly either
+      ``i386`` for 32-bit Intel platforms
+      or ``x86_64`` for 64-bit Intel (and AMD) platforms.
+      Other valid values for ``<architecture>`` on Linux include
+      ``aarch64``, ``arm``, ``mips``, ``ppc``, ``powerpc``, ``s390``,
+      and ``sparc``.
+
+    * ``<os>`` is always ``linux-gnu``, except for extensions built to
+      talk to the 32-bit ABI on 64-bit platforms, in which case it is
+      ``linux-gnu32`` (and ``<architecture>`` will be ``x86_64``).
+
+  * On Windows, extension module filenames end with
+    ``<debug>.cp<major><minor>-<platform>.pyd``:
+
+    * ``<major>`` is the major number of the Python version;
+      for Python 3.5 this is ``3``.
+
+    * ``<minor>`` is the minor number of the Python version;
+      for Python 3.5 this is ``5``.
+
+    * ``<platform>`` is the platform the extension module was built for,
+      either ``win32`` for Win32,
+      ``win_amd64`` for Win64,
+      ``win_ia64`` for Windows Itanium 64,
+      and ``win_arm`` for Windows on ARM.
+
+    * If built in debug mode, ``<debug>`` will be ``_d``,
+      otherwise it will be blank.
+
+  * On OS X platforms, extension module filenames now end with
+    ``-darwin.so``.
+
+  * On all other platforms, extension module filenames are the
+    same as they were with Python 3.4.
+
 * New ``calloc`` functions:
 
   * :c:func:`PyMem_RawCalloc`