Follow up from https://github.com/python/peps/pull/712GH-issuecomment-403591108:

"people using the repo without using GitHub still ought to be reminded of the COC" - GvR
(cherry picked from commit 3ed91929)
Co-authored-by: Mariatta <Mariatta@users.noreply.github.com>

Initial patch by Joshua Jay Herman.
(cherry picked from commit 9863de03)
Co-authored-by: Berker Peksag <berker.peksag@gmail.com>

(cherry picked from commit f60bf0e1)
Co-authored-by: Serhiy Storchaka <storchaka@gmail.com>

Fixed also testing the "always" warning filter.
(cherry picked from commit b796e7dc)
Co-authored-by: Sergey Fedoseev <fedoseev.sergey@gmail.com>

Include a more easily understood example for nullcontext
(cherry picked from commit c287545d)
Co-authored-by: Daniel Porteous <danielporteous1@gmail.com>

The 'output formatting' section of the tutorial talks a lot about manual formatting with things like .rjust() and .zfill(), with only a passing reference to 3.6's new f-strings.

This doesn't drop all of the old material, but it does rearrange the topics into a more modern order: f-strings first, discussing formatting specifiers a bit; then calling .format(); finally manual formatting with .ljust().
(cherry picked from commit ced350b1)
Co-authored-by: Andrew Kuchling <amk@amk.ca>

This will prevent emitting a resource warning when the execution was
interrupted by Ctrl-C between calling open() and entering a 'with' block
in "with open()".
(cherry picked from commit 3f4d90d4)
Co-authored-by: Serhiy Storchaka <storchaka@gmail.com>

(cherry picked from commit 2a9b8bab)

(cherry picked from commit f85af035)
Co-authored-by: Andrés Delfino <adelfino@gmail.com>

(cherry picked from commit bc9aa813)
Co-authored-by: Marcin Niemira <marcin@niemira.net>

webbrowser._synthesize() called webbrowser.register() with
outdated signature.
Co-Authored-By: John Still <john@jmsdvl.com>
(cherry picked from commit 25b804a9)
Co-authored-by: Serhiy Storchaka <storchaka@gmail.com>

Make the change where discussing the CPython implementation of lists and dicts.
(cherry picked from commit 8d412780)
Co-authored-by: Andrés Delfino <adelfino@gmail.com>

(cherry picked from commit 9c5ba097)
Co-authored-by: Marcin Niemira <marcin@niemira.net>

(cherry picked from commit 9b50a7f2)
Co-authored-by: Benjamin Peterson <benjamin@python.org>

(cherry picked from commit caccca78)
Co-authored-by: Andrés Delfino <adelfino@gmail.com>

(cherry picked from commit b6bb77c2)
Co-authored-by: Andrés Delfino <adelfino@gmail.com>

(cherry picked from commit 2d748389)
Co-authored-by: Andrés Delfino <adelfino@gmail.com>

(cherry picked from commit 03dd0e79)
Co-authored-by: Andrés Delfino <adelfino@gmail.com>

(cherry picked from commit 6cfe45a5)
Co-authored-by: Benjamin Peterson <benjamin@python.org>

(cherry picked from commit 2800dcf6)
Co-authored-by: Dong-hee Na <donghee.na92@gmail.com>

"can be used do declare" → "can be used to declare"
(cherry picked from commit 86bfed37)
Co-authored-by: João D. Ferreira <jotomicron@gmail.com>

(cherry picked from commit cb4bae72)
Co-authored-by: Benjamin Peterson <benjamin@python.org>

* Always return bytes from _HackedGetData.get_data().

Ensure the imp.load_source shim always returns bytes by reopening the file in
binary mode if needed. Hash-based pycs have to receive the source code in bytes.

It's tempting to change imp.get_suffixes() to always return 'rb' as a mode, but
that breaks some stdlib tests and likely 3rdparty code, too.
(cherry picked from commit b0274f2c)
Co-authored-by: Benjamin Peterson <benjamin@python.org>

(cherry picked from commit 0b752287)
Co-authored-by: Yury Selivanov <yury@magic.io>

The multiprocessing module now uses the monotonic clock
time.monotonic() instead of the system clock time.time() to implement
timeouts.
(cherry picked from commit c2368cbc)
Co-authored-by: Victor Stinner <vstinner@redhat.com>

(cherry picked from commit 6f19fc6d)
Co-authored-by: Robert Krzyzanowski <technoguyrob@gmail.com>

[3.7] bpo-33899: Make tokenize module mirror end-of-file is end-of-line behavior (GH-7891) (GH-8132)

Most of the change involves fixing up the test suite, which previously made
the assumption that there wouldn't be a new line if the input didn't end in
one.

Contributed by Ammar Askar.

(cherry picked from commit c4ef4896)

(cherry picked from commit d8c3e820)
Co-authored-by: Zackery Spytz <zspytz@gmail.com>

The line is speaking of a list of commands, not the list command.
(cherry picked from commit 7943c5e8)
Co-authored-by: Julien Palard <julien@palard.fr>

It was moved from bitbucket to GitHub.

(cherry picked from commit a6e1e41e)

(cherry picked from commit 3c8aae9f)
Co-authored-by: Benjamin Peterson <benjamin@python.org>

(cherry picked from commit e55ca3fd)
Co-authored-by: Artjom <tjomk@users.noreply.github.com>

subprocess.Popen now copies the startupinfo argument to leave it
unchanged: it will modify the copy, so that the same STARTUPINFO
object can be used multiple times.

Add subprocess.STARTUPINFO._copy() private method.

Python 3.7 backport from master makes the copy() private: renamed to
_copy().

(cherry picked from commit 483422f5)

Use DeprecationWarning instead of PendingDeprecationWarning.

(cherry picked from commit 09bb918a)
Co-authored-by: Serhiy Storchaka <storchaka@gmail.com>

(cherry picked from commit fc05e68d)
Co-authored-by: Serhiy Storchaka <storchaka@gmail.com>

(cherry picked from commit 3a9bb5f2)
Co-authored-by: Sergey Fedoseev <fedoseev.sergey@gmail.com>

This commit fixes the -timedelta overfllow issue not documented properly.
Signed-off-by: Farhaan Bukhsh <farhaan.bukhsh@gmail.com>
(cherry picked from commit 5b6e49a1)
Co-authored-by: Farhaan Bukhsh <farhaan.bukhsh@gmail.com>

Result of function interpreter_requires_environment() depends on os.environ.
This was not covered by the tests, leading to fail when PYTHONHOME was set.
(cherry picked from commit a390cb6b)
Co-authored-by: Lorenz Mende <Lorenz.mende@gmail.com>

Fix test_forkserver_sigkill() of test_multiprocessing_forkserver:
give more time to the first child process to complete, double the
sleep in the parent process.

Reduce also the child process sleep from 1000 ms to 500 ms, to not change
the total duration of the test.
(cherry picked from commit 07888e1c)
Co-authored-by: Victor Stinner <vstinner@redhat.com>