Issue #16316: mimetypes now recognizes the .xz and .txz (.tar.xz) extensions.
#7855: Add tests for ctypes/winreg for issues found in IronPython.  Initial patch by Dino Viehland.
#16518: use "bytes-like object" throughout the docs.
Elaborate on bytes-like objects.
Issue #17408: Avoid using an obsolete instance of the copyreg module when the interpreter is shutdown and then started again.
Issue #14173: Avoid crashing when reading a signal handler during interpreter shutdown.
Fix a test to not use an assertion for something that could be
legitimately false.