diff --git a/doc/whats-new.rst b/doc/whats-new.rst
index 7ca81338b6a..e7a281485fb 100644
--- a/doc/whats-new.rst
+++ b/doc/whats-new.rst
@@ -6,10 +6,14 @@
 What's New
 ==========
 
-.. _whats-new.2025.11.1:
+.. _whats-new.2025.12.0:
 
-v2025.11.1 (unreleased)
+v2025.12.0 (unreleased)
 -----------------------
+This release rolls back the default engine for HTTP urls, adds support for :py:class:`DataTree` objects in ``combine_nested`` and contains numerous bug fixes.
+
+Thanks to the 16 contributors to this release:
+Benoit Bovy, Christine P. Chai, Deepak Cherian, Dhruva Kumar Kaushal, Ian Hunt-Isaak, Ilan Gold, Illviljan, Julia Signell, Justus Magin, Lars Buntemeyer, Maximilian Roos, Miguel Jimenez, Nick Hodgskin, Richard Berg, Spencer Clark and Stephan Hoyer
 
 New Features
 ~~~~~~~~~~~~
@@ -18,25 +22,15 @@ New Features
   when downloading dap4 (opendap) dimensions data (:issue:`10628`, :pull:`10629`). In addition ``checksums=True|False``
   is added as optional argument to be passed to ``pydap`` backend.
   By `Miguel Jimenez-Urias <https://github.com/Mikejmnez>`_.
-
-- :py:func:`combine_nested` now support :py:class:`DataTree` objects
-  (:pull:`10849`).
+- :py:func:`combine_nested` now supports :py:class:`DataTree` objects (:pull:`10849`).
   By `Stephan Hoyer <https://github.com/shoyer>`_.
 
-Breaking Changes
-~~~~~~~~~~~~~~~~
-
-
-Deprecations
-~~~~~~~~~~~~
-
-
 Bug Fixes
 ~~~~~~~~~
 
 - When assigning an indexed coordinate to a data variable or coordinate, coerce it from
-  ``IndexVariable`` to ``Variable`` (:issue:`9859`, :issue:`10829`, :pull:`10909`)
-  By `Julia Signell <https://github.com/jsignell>`_
+  ``IndexVariable`` to ``Variable`` (:issue:`9859`, :issue:`10829`, :pull:`10909`).
+  By `Julia Signell <https://github.com/jsignell>`_.
 - The NetCDF4 backend will now claim to be able to read any URL except for one that contains
   the substring zarr. This restores backward compatibility after
   :pull:`10804` broke workflows that relied on ``xr.open_dataset("http://...")``
@@ -48,17 +42,19 @@ Bug Fixes
   By `Justus Magin <https://github.com/keewis>`_.
 - Support decoding unsigned integers to ``np.timedelta64``.
   By `Deepak Cherian <https://github.com/dcherian>`_.
-
+- Properly handle internal type promotion and ``NA`` objects for extension arrays (:pull:`10423`).
+  By `Ilan Gold <https://github.com/ilan-gold>`_.
 
 Documentation
 ~~~~~~~~~~~~~
 
 - Added section on the `limitations of cftime arithmetic <https://docs.xarray.dev/en/stable/user-guide/weather-climate.html#arithmetic-limitations-with-non-standard-calendars>`_ (:pull:`10653`).
-  By `Lars Buntemeyer <https://github.com/larsbuntemeyer>`_
+  By `Lars Buntemeyer <https://github.com/larsbuntemeyer>`_.
 
 Internal Changes
 ~~~~~~~~~~~~~~~~
-
+- Change the development workflow to use ``pixi`` (:issue:`10732`, :pull:`10888`).
+  By `Nick Nodgskin <https://github.com/VeckoTheGecko>`_.
 
 .. _whats-new.2025.11.0:
 
diff --git a/pixi.toml b/pixi.toml
index acec12d9f0f..f7f80674d22 100644
--- a/pixi.toml
+++ b/pixi.toml
@@ -279,6 +279,13 @@ pre-commit = "*"
 [feature.pre-commit.tasks]
 pre-commit = { cmd = "pre-commit" }
 
+[feature.release.dependencies]
+gitpython = "*"
+cytoolz = "*"
+
+[feature.release.tasks]
+release-contributors = "python ci/release_contributors.py"
+
 [environments]
 # Testing
 # test-just-xarray = { features = ["test"] } # https://github.com/pydata/xarray/pull/10888/files#r2511336147
@@ -378,3 +385,4 @@ doc = { features = [
   "extras",
 ] }
 pre-commit = { features = ["pre-commit"], no-default-feature = true }
+release = { features = ["release"], no-default-feature = true }