Issue #10747: Use versioned labels in the Windows start menu.
Patch by Olive Kilburn.
asyncio: BaseEventLoop._assert_is_current_event_loop() now only raises an
exception if the current loop is not None.

Guido van Rossum wrote:

"The behavior that you can set the loop to None (and keep track of it
explicitly) is part of the spec, and this should still be supported even in
debug mode. The behavior that we raise an error if you are caught having
multiple active loops per thread is just a debugging heuristic, and it
shouldn't break code that follows the spec."
asyncio: Enable the debug mode of event loops when the PYTHONASYNCIODEBUG
environment variable is set
asyncio: Add an unit test to check that setting the PYTHONASYNCIODEBUG env var
enables debug mode of the event loop.
asyncio, Tulip issue 172: only log selector timing in debug mode
asyncio: document the debug mode
asyncio, Tulip issue 171: BaseEventLoop.close() now raises an exception if the
event loop is running. You must first stop the event loop and then wait until
it stopped, before closing it.
some timezone doc improvements (closes #16667)

From the combined efforts of Berber Peksage, Andrew Svetlov, and Yayoi Ukai.
clarify that islink only really works if python knows about symlinks (closes #13143)

Patch from Yayoi Ukai.
Issue #8343: Named group error msgs did not show the group name.