gh-137586: Address hugovk post-approval concerns

Move webbrowser entry in Doc/deprecations/pending-removal-in-3.17.rst
to after typing, to maintain alphabetical order.

Move import plistlib to after import threading, per isort/Ruff style
of placing stdlib imports after the main import block.

Fix :class:`!MacOSX` -> :class:`!MacOS` in the Library NEWS entry.

Remove extra blank line in MacOSXOSAScriptTest.mock_popen.

Add webbrowser entries to Doc/whatsnew/3.15.rst: one under "Improved
modules" describing the new MacOS class, and one under "New
deprecations" for MacOSXOSAScript scheduled removal in 3.17.

Author: secengjeff

Doc/whatsnew/3.15.rst

@@ -1390,6 +1390,19 @@ wave
 (Contributed by Lionel Koenig and Michiel W. Beijen in :gh:`60729`.)
 
 
+webbrowser
+----------
+
+* On macOS, the new :class:`~webbrowser.MacOS` class opens URLs via
+  :program:`/usr/bin/open` instead of constructing and executing AppleScript
+  via :program:`osascript`. The default browser is detected from the
+  LaunchServices preferences file using :mod:`plistlib`, with
+  :class:`!com.apple.Safari` as the fallback on fresh installations.
+  For non-HTTP(S) URLs, :program:`open -b <bundle-id>` is used to route the
+  URL through a browser rather than the OS file handler, preventing
+  file injection attacks.
+  (Contributed by Jeff Lyon in :gh:`137586`.)
+
 xml.parsers.expat
 -----------------
 
@@ -1780,6 +1793,12 @@ New deprecations
     merely imported or accessed from the :mod:`!typing` module.
 
 
+* :mod:`webbrowser`:
+
+  * :class:`~webbrowser.MacOSXOSAScript` is deprecated in favour of
+    :class:`~webbrowser.MacOS` and scheduled for removal in Python 3.17.
+    (Contributed by Jeff Lyon in :gh:`137586`.)
+
 * ``__version__``
 
   * The ``__version__``, ``version`` and ``VERSION`` attributes have been

Lib/test/test_webbrowser.py

@@ -431,7 +431,6 @@ def mock_popen(self, cmd, mode):
         self.popen_pipe = MockPopenPipe(cmd, mode)
         return self.popen_pipe
 
-
     def test_default_open(self):
         url = "https://python.org"
         self.browser.open(url)

Misc/NEWS.d/next/Library/2026-03-26-01-42-20.gh-issue-137586.KmHRwR.rst

@@ -1,3 +1,3 @@
-Add :class:`!MacOSX` to :mod:`webbrowser` for macOS, which opens URLs via
+Add :class:`!MacOS` to :mod:`webbrowser` for macOS, which opens URLs via
 ``/usr/bin/open`` instead of piping AppleScript to ``osascript``.
 Deprecate :class:`!MacOSXOSAScript` in favour of :class:`!MacOS`.