diff --git a/Makefile b/Makefile
index 3ce4eda956d..12f4f302a8b 100644
--- a/Makefile
+++ b/Makefile
@@ -41,7 +41,7 @@ test-no-testing-data: in
 	$(PYTESTS) mne
 
 test-doc: sample_data testing_data
-	$(PYTESTS) --tb=short --cov=mne --cov-report=xml --cov-branch --doctest-modules --doctest-ignore-import-errors --doctest-glob='*.rst' ./doc/ --ignore=./doc/auto_examples --ignore=./doc/auto_tutorials --ignore=./doc/_build --ignore=./doc/conf.py --ignore=doc/sphinxext --fulltrace
+	$(PYTESTS) --tb=short --cov=mne --cov-report=xml --cov-branch --doctest-modules --doctest-ignore-import-errors --doctest-glob='*.rst' ./doc/ --ignore=./doc/auto_examples --ignore=./doc/auto_tutorials --ignore=./doc/_build --ignore=./doc/conf.py --ignore=./doc/jupyter_lite_config.py --ignore=doc/sphinxext --fulltrace
 
 pre-commit:
 	@pre-commit run -a --show-diff-on-failure
diff --git a/azure-pipelines.yml b/azure-pipelines.yml
index d85b5999387..02df54ffd81 100644
--- a/azure-pipelines.yml
+++ b/azure-pipelines.yml
@@ -196,6 +196,10 @@ stages:
           UV_SYSTEM_PYTHON: 'true'  # UsePythonVersion gives us a bare interpreter, not a venv
           UV_NO_PROGRESS: 'true'
           AZURE_CI_WINDOWS: 'true'
+          # Mesa's llvmpipe rasterizer threads can deadlock at process exit on
+          # Windows (pyvista/setup-headless-display-action#55); the action sets
+          # this itself on GHA, but here we only run its install script
+          LP_NUM_THREADS: '0'
           MNE_CI_KIND: $(TEST_MODE)
           MNE_TEST_ALLOW_SKIP: $(MNE_TEST_ALLOW_SKIP)
         timeoutInMinutes: 40
diff --git a/doc/changes/dev/14314.other.rst b/doc/changes/dev/14314.other.rst
new file mode 100644
index 00000000000..43a577fb668
--- /dev/null
+++ b/doc/changes/dev/14314.other.rst
@@ -0,0 +1 @@
+Lock the JupyterLite browser kernel's extra packages at build time instead of installing them from the first notebook cell, by `Teon Brooks`_.
diff --git a/doc/conf.py b/doc/conf.py
index f28d499f539..e64423e5635 100644
--- a/doc/conf.py
+++ b/doc/conf.py
@@ -505,6 +505,8 @@
     # sphinx-gallery writes link to auto_*/... at the root
     jupyterlite_contents = ["jupyterlite_contents/auto_*"]
     jupyterlite_bind_ipynb_suffix = False
+    # bakes the browser's extra packages into the Pyodide lock at build time
+    jupyterlite_config = "jupyter_lite_config.py"
     # served at the docs root (/mne_data/...) through html_extra_path below
     stage_lite_data(curpath / "lite_extra" / "mne_data")
 
diff --git a/doc/jupyter_lite_config.py b/doc/jupyter_lite_config.py
new file mode 100644
index 00000000000..07dd5b34af3
--- /dev/null
+++ b/doc/jupyter_lite_config.py
@@ -0,0 +1,30 @@
+"""Build-time config for the JupyterLite site's Pyodide lock.
+
+Adds MNE and the packages the notebooks import to the lock, so Pyodide loads
+them at kernel initialization. Packages Pyodide already curates keep their
+curated version.
+"""
+
+# Authors: The MNE-Python contributors.
+# License: BSD-3-Clause
+# Copyright the MNE-Python contributors.
+
+import sys
+from pathlib import Path
+
+sys.path.append(str(Path(__file__).parent / "sphinxext"))
+
+from jupyterlite_lock_specs import (  # noqa: E402
+    jupyterlite_package_names,
+    jupyterlite_specs_to_lock,
+)
+
+c = get_config()  # noqa: F821
+
+c.PyodideLockAddon.enabled = True
+# the MNE wheel build_lite_wheel.py builds from this checkout (a tagged
+# checkout gives the release): the solve takes it over PyPI, which would
+# otherwise supply the latest release through mne-connectivity's mne>=1.6
+c.PyodideLockAddon.wheels = ["pypi"]
+c.PyodideLockAddon.specs = ["mne", *jupyterlite_specs_to_lock()]
+c.PyodideLockAddon.prefetch_extra = ["mne", *jupyterlite_package_names()]
diff --git a/doc/sphinxext/jupyterlite_data.py b/doc/sphinxext/jupyterlite_data.py
index 829380b4d3d..8fb06084220 100644
--- a/doc/sphinxext/jupyterlite_data.py
+++ b/doc/sphinxext/jupyterlite_data.py
@@ -175,9 +175,7 @@ def stage_lite_data(dst_base):
     sphinx_logger.info(
         f"[JupyterLite] Served data: {n_copied} files copied, {n_missing} missing"
     )
-    # the development wheel, so the browser installs this MNE rather than the
-    # PyPI release: doc/sphinxext/build_lite_wheel.py puts it in doc/pypi, where
-    # the piplite addon indexes it; `make html` runs that first, so this is
-    # only a fallback for a bare sphinx-build
+    # the MNE wheel jupyter_lite_config.py locks for the browser: `make html`
+    # builds it first, so this is only a fallback for a bare sphinx-build
     wheels = find_wheels() or build_wheel()
     sphinx_logger.info(f"[JupyterLite] MNE wheel for the browser kernel: {wheels}")
diff --git a/doc/sphinxext/jupyterlite_lock_specs.py b/doc/sphinxext/jupyterlite_lock_specs.py
new file mode 100644
index 00000000000..ab795596d4b
--- /dev/null
+++ b/doc/sphinxext/jupyterlite_lock_specs.py
@@ -0,0 +1,48 @@
+"""Specs to add to Pyodide's lock for JupyterLite, versus what it already curates.
+
+Naming a package in ``PyodideLockAddon.specs`` drops its existing pin from
+the lock (see ``pyodide_lock.uv_pip_compile.constraints_txt``) and resolves
+it fresh from PyPI instead, a smaller and differently versioned set than
+Pyodide's own curated wheels. :func:`jupyterlite_specs_to_lock` avoids that
+by only including specs Pyodide's own lock does not already satisfy.
+"""
+
+# Authors: The MNE-Python contributors.
+# License: BSD-3-Clause
+# Copyright the MNE-Python contributors.
+
+import json
+import tomllib
+import urllib.request
+from pathlib import Path
+
+from jupyterlite_pyodide_kernel.constants import PYODIDE_LOCK_DEFAULT_URL
+from packaging.requirements import Requirement
+from packaging.utils import canonicalize_name
+
+_PYPROJECT_TOML = Path(__file__).parents[2] / "pyproject.toml"
+
+
+def jupyterlite_specs():
+    """Retrieve the "jupyterlite" dependency group from pyproject.toml."""
+    with open(_PYPROJECT_TOML, "rb") as fid:
+        return tomllib.load(fid)["dependency-groups"]["jupyterlite"]
+
+
+def jupyterlite_package_names():
+    """Canonical package names in the "jupyterlite" dependency group."""
+    return [canonicalize_name(Requirement(spec).name) for spec in jupyterlite_specs()]
+
+
+def jupyterlite_specs_to_lock():
+    """Retrieve specs from "jupyterlite" group Pyodide does not already satisfy."""
+    with urllib.request.urlopen(PYODIDE_LOCK_DEFAULT_URL) as fid:
+        curated = json.load(fid)["packages"]
+
+    to_lock = []
+    for spec in jupyterlite_specs():
+        req = Requirement(spec)
+        pkg = curated.get(canonicalize_name(req.name))
+        if pkg is None or not req.specifier.contains(pkg["version"]):
+            to_lock.append(spec)
+    return to_lock
diff --git a/doc/sphinxext/jupyterlite_setup_cell.py b/doc/sphinxext/jupyterlite_setup_cell.py
index f0bd1b55c26..bfa631523fe 100644
--- a/doc/sphinxext/jupyterlite_setup_cell.py
+++ b/doc/sphinxext/jupyterlite_setup_cell.py
@@ -1,12 +1,11 @@
 """The setup cell prepended to every JupyterLite notebook.
 
-It installs MNE into the browser kernel and hands over to
-``mne.viz.backends._jupyterlite.setup_notebook``, which patches what Pyodide
-does not provide. piplite (not micropip) prefers the development MNE wheel
-bundled with the docs over PyPI, and ``keep_going`` reports a dependency with
-no wheel instead of aborting. ``sys.platform`` is ``"emscripten"`` only inside
-Pyodide, so the cell is a no-op in a local kernel and a notebook downloaded
-from inside JupyterLite runs unchanged there.
+It hands over to ``mne.viz.backends._jupyterlite.setup_notebook``, which
+patches what Pyodide does not provide; MNE itself and the packages the
+notebooks import are in the Pyodide lock (see ``jupyter_lite_config.py``).
+``sys.platform`` is ``"emscripten"`` only inside Pyodide, so the cell is a
+no-op in a local kernel and a notebook downloaded from inside JupyterLite runs
+unchanged there.
 
 The docs build prepends it only to the notebooks copied into the JupyterLite
 contents, not through ``first_notebook_cell``, which would also put it in the
@@ -17,24 +16,15 @@
 # License: BSD-3-Clause
 # Copyright the MNE-Python contributors.
 
-# ruff: noqa: E501  # the install list stays on one line so the cell reads short
-
-import ast
-
 LITE_SETUP_CELL = """\
-# 💡 Added by the docs build: installs MNE into the browser kernel and adapts
-# it to Pyodide. Does nothing outside JupyterLite.
+# 💡 Added by the docs build: adapts MNE to Pyodide. Does nothing outside
+# JupyterLite.
 import sys
 
 if sys.platform == "emscripten":
-    import piplite
-
-    await piplite.install(["mne", "scikit-learn", "joblib", "pandas", "seaborn", "mne-connectivity", "nibabel", "pyvista-js", "pyxdf", "mffpy", "python-picard"], keep_going=True)  # noqa: E501
     from mne.viz.backends._jupyterlite import setup_notebook
 
     setup_notebook()
 """
 # nothing else runs this before a reader does, so at least make sure it parses
-compile(
-    LITE_SETUP_CELL, "lite_setup_cell", "exec", flags=ast.PyCF_ALLOW_TOP_LEVEL_AWAIT
-)
+compile(LITE_SETUP_CELL, "lite_setup_cell", "exec")
diff --git a/mne/datasets/_fetch.py b/mne/datasets/_fetch.py
index 6ae66814dc4..0151e60dca8 100644
--- a/mne/datasets/_fetch.py
+++ b/mne/datasets/_fetch.py
@@ -126,7 +126,8 @@ def fetch_dataset(
         {'dataset_name': 'sample',
          'archive_name': 'MNE-sample-data-processed.tar.gz',
          'hash': 'md5:e8f30c4516abdc12a0c08e6bae57409c',
-         'url': 'https://osf.io/download/86qa2?version=6',
+         'url': 'https://github.com/mne-tools/mne-data/releases/download/'
+                'sample-6/MNE-sample-data-processed.tar.gz',
          'folder_name': 'MNE-sample-data',
          'config_key': 'MNE_DATASETS_SAMPLE_PATH'}
 
diff --git a/mne/datasets/_fsaverage/base.py b/mne/datasets/_fsaverage/base.py
index cb69b6092b3..1bbecb3851d 100644
--- a/mne/datasets/_fsaverage/base.py
+++ b/mne/datasets/_fsaverage/base.py
@@ -77,13 +77,13 @@ def fetch_fsaverage(subjects_dir=None, *, verbose=None):
     _manifest_check_download(
         manifest_path=FSAVERAGE_MANIFEST_PATH / "root.txt",
         destination=subjects_dir,
-        url="https://osf.io/download/3bxqt?version=2",
+        url="https://github.com/mne-tools/mne-data/releases/download/fsaverage-1.0/fsaverage-root.zip",
         hash_="5133fe92b7b8f03ae19219d5f46e4177",
     )
     _manifest_check_download(
         manifest_path=FSAVERAGE_MANIFEST_PATH / "bem.txt",
         destination=subjects_dir / "fsaverage",
-        url="https://osf.io/download/7ve8g?version=4",
+        url="https://github.com/mne-tools/mne-data/releases/download/fsaverage-1.0/fsaverage-bem.zip",
         hash_="b31509cdcf7908af6a83dc5ee8f49fb1",
     )
     return fs_dir
diff --git a/mne/datasets/_phantom/base.py b/mne/datasets/_phantom/base.py
index dcafb4edaf0..a9dcaa0667f 100644
--- a/mne/datasets/_phantom/base.py
+++ b/mne/datasets/_phantom/base.py
@@ -60,7 +60,7 @@ def fetch_phantom(kind="otaniemi", subjects_dir=None, *, verbose=None):
     """
     phantoms = dict(
         otaniemi=dict(
-            url="https://osf.io/download/j5czy?version=1",
+            url="https://github.com/mne-tools/mne-data/releases/download/phantom_otaniemi-1/phantom_otaniemi.zip",
             hash="42d17db5b1db3e30327ffb4cf2649de8",
         ),
     )
diff --git a/mne/datasets/config.py b/mne/datasets/config.py
index 0e2c581f450..8b7ade4e9ff 100644
--- a/mne/datasets/config.py
+++ b/mne/datasets/config.py
@@ -140,7 +140,7 @@
 MNE_DATASETS["fnirs_motor"] = dict(
     archive_name="MNE-fNIRS-motor-data.tgz",
     hash="md5:c4935d19ddab35422a69f3326a01fef8",
-    url="https://osf.io/download/dj3eh?version=1",
+    url="https://github.com/mne-tools/mne-data/releases/download/fnirs_motor-1/MNE-fNIRS-motor-data.tgz",
     folder_name="MNE-fNIRS-motor-data",
     config_key="MNE_DATASETS_FNIRS_MOTOR_PATH",
 )
@@ -148,7 +148,8 @@
 MNE_DATASETS["ucl_opm_auditory"] = dict(
     archive_name="auditory_OPM_stationary.zip",
     hash="md5:b2d69aa2d656b960bd0c18968dc1a14d",
-    url="https://osf.io/download/tp324?version=1",  # original is mwrt3
+    # original is https://osf.io/mwrt3
+    url="https://github.com/mne-tools/mne-data/releases/download/ucl_opm_auditory-1/auditory_OPM_stationary.zip",
     folder_name="auditory_OPM_stationary",
     config_key="MNE_DATASETS_UCL_OPM_AUDITORY_PATH",
 )
@@ -156,7 +157,7 @@
 MNE_DATASETS["kiloword"] = dict(
     archive_name="MNE-kiloword-data.tar.gz",
     hash="md5:3a124170795abbd2e48aae8727e719a8",
-    url="https://osf.io/download/qkvf9?version=1",
+    url="https://github.com/mne-tools/mne-data/releases/download/kiloword-1/MNE-kiloword-data.tar.gz",
     folder_name="MNE-kiloword-data",
     config_key="MNE_DATASETS_KILOWORD_PATH",
 )
@@ -172,7 +173,7 @@
 MNE_DATASETS["opm"] = dict(
     archive_name="MNE-OPM-data.tar.gz",
     hash="md5:370ad1dcfd5c47e029e692c85358a374",
-    url="https://osf.io/download/p6ae7?version=2",
+    url="https://github.com/mne-tools/mne-data/releases/download/opm-2/MNE-OPM-data.tar.gz",
     folder_name="MNE-OPM-data",
     config_key="MNE_DATASETS_OPM_PATH",
 )
@@ -180,7 +181,7 @@
 MNE_DATASETS["phantom_kit"] = dict(
     archive_name="MNE-phantom-KIT-data.tar.gz",
     hash="md5:7bfdf40bbeaf17a66c99c695640e0740",
-    url="https://osf.io/download/fb6ya?version=1",
+    url="https://github.com/mne-tools/mne-data/releases/download/phantom_kit-1/MNE-phantom-KIT-data.tar.gz",
     folder_name="MNE-phantom-KIT-data",
     config_key="MNE_DATASETS_PHANTOM_KIT_PATH",
 )
@@ -188,7 +189,7 @@
 MNE_DATASETS["phantom_4dbti"] = dict(
     archive_name="MNE-phantom-4DBTi.zip",
     hash="md5:938a601440f3ffa780d20a17bae039ff",
-    url="https://osf.io/download/v2brw?version=2",
+    url="https://github.com/mne-tools/mne-data/releases/download/phantom_4dbti-2/MNE-phantom-4DBTi.zip",
     folder_name="MNE-phantom-4DBTi",
     config_key="MNE_DATASETS_PHANTOM_4DBTI_PATH",
 )
@@ -196,7 +197,7 @@
 MNE_DATASETS["phantom_kernel"] = dict(
     archive_name="MNE-phantom-kernel.tar.gz",
     hash="md5:4e2ad987dac1a20f95bae8ffeb2d41d6",
-    url="https://osf.io/download/dj7wz?version=1",
+    url="https://github.com/mne-tools/mne-data/releases/download/phantom_kernel-1/MNE-phantom-kernel.tar.gz",
     folder_name="MNE-phantom-kernel-data",
     config_key="MNE_DATASETS_PHANTOM_KERNEL_PATH",
 )
@@ -204,7 +205,7 @@
 MNE_DATASETS["sample"] = dict(
     archive_name="MNE-sample-data-processed.tar.gz",
     hash="md5:e8f30c4516abdc12a0c08e6bae57409c",
-    url="https://osf.io/download/86qa2?version=6",
+    url="https://github.com/mne-tools/mne-data/releases/download/sample-6/MNE-sample-data-processed.tar.gz",
     folder_name="MNE-sample-data",
     config_key="MNE_DATASETS_SAMPLE_PATH",
 )
@@ -221,7 +222,7 @@
 MNE_DATASETS["somato"] = dict(
     archive_name="MNE-somato-data.tar.gz",
     hash="md5:9a191907b326b9402341ee7a0d1240d8",
-    url="https://osf.io/download/tp4sg?version=8",
+    url="https://github.com/mne-tools/mne-data/releases/download/somato-8/MNE-somato-data.tar.gz",
     folder_name="MNE-somato-data",
     config_key="MNE_DATASETS_SOMATO_PATH",
 )
@@ -229,7 +230,7 @@
 MNE_DATASETS["spm"] = dict(
     archive_name="MNE-spm-face.tar.gz",
     hash="md5:9f43f67150e3b694b523a21eb929ea75",
-    url="https://osf.io/download/je4s8?version=2",
+    url="https://github.com/mne-tools/mne-data/releases/download/spm-2/MNE-spm-face.tar.gz",
     folder_name="MNE-spm-face",
     config_key="MNE_DATASETS_SPM_FACE_PATH",
 )
@@ -241,17 +242,32 @@
     folder_name="MNE-visual_92_categories-data",
     config_key="MNE_DATASETS_VISUAL_92_CATEGORIES_PATH",
 )
+# four parts, each under GitHub's 2 GiB release-asset limit
 MNE_DATASETS["visual_92_categories_1"] = dict(
     archive_name="MNE-visual_92_categories-data-part1.tar.gz",
-    hash="md5:74f50bbeb65740903eadc229c9fa759f",
-    url="https://osf.io/download/8ejrs?version=1",
+    hash="md5:b7ee73c69c1c086354ae370c66b41f0b",
+    url="https://github.com/mne-tools/mne-data/releases/download/visual_92_categories-2/MNE-visual_92_categories-data-part1.tar.gz",
     folder_name="MNE-visual_92_categories-data",
     config_key="MNE_DATASETS_VISUAL_92_CATEGORIES_PATH",
 )
 MNE_DATASETS["visual_92_categories_2"] = dict(
     archive_name="MNE-visual_92_categories-data-part2.tar.gz",
-    hash="md5:203410a98afc9df9ae8ba9f933370e20",
-    url="https://osf.io/download/t4yjp?version=1",
+    hash="md5:f35b89c76a76f2341e68d60b46578621",
+    url="https://github.com/mne-tools/mne-data/releases/download/visual_92_categories-2/MNE-visual_92_categories-data-part2.tar.gz",
+    folder_name="MNE-visual_92_categories-data",
+    config_key="MNE_DATASETS_VISUAL_92_CATEGORIES_PATH",
+)
+MNE_DATASETS["visual_92_categories_3"] = dict(
+    archive_name="MNE-visual_92_categories-data-part3.tar.gz",
+    hash="md5:94b68c9c3ce267cc82106518129c6221",
+    url="https://github.com/mne-tools/mne-data/releases/download/visual_92_categories-2/MNE-visual_92_categories-data-part3.tar.gz",
+    folder_name="MNE-visual_92_categories-data",
+    config_key="MNE_DATASETS_VISUAL_92_CATEGORIES_PATH",
+)
+MNE_DATASETS["visual_92_categories_4"] = dict(
+    archive_name="MNE-visual_92_categories-data-part4.tar.gz",
+    hash="md5:59b0296b2ef1763481e6e5123b0ca207",
+    url="https://github.com/mne-tools/mne-data/releases/download/visual_92_categories-2/MNE-visual_92_categories-data-part4.tar.gz",
     folder_name="MNE-visual_92_categories-data",
     config_key="MNE_DATASETS_VISUAL_92_CATEGORIES_PATH",
 )
@@ -259,14 +275,14 @@
 MNE_DATASETS["mtrf"] = dict(
     archive_name="mTRF_1.5.zip",
     hash="md5:273a390ebbc48da2c3184b01a82e4636",
-    url="https://osf.io/download/h85s2?version=1",
+    url="https://github.com/mne-tools/mne-data/releases/download/mtrf-1/mTRF_1.5.zip",
     folder_name="mTRF_1.5",
     config_key="MNE_DATASETS_MTRF_PATH",
 )
 MNE_DATASETS["refmeg_noise"] = dict(
     archive_name="sample_reference_MEG_noise-raw.zip",
     hash="md5:779fecd890d98b73a4832e717d7c7c45",
-    url="https://osf.io/download/drt6v?version=1",
+    url="https://github.com/mne-tools/mne-data/releases/download/refmeg_noise-1/sample_reference_MEG_noise-raw.zip",
     folder_name="MNE-refmeg-noise-data",
     config_key="MNE_DATASETS_REFMEG_NOISE_PATH",
 )
@@ -274,7 +290,7 @@
 MNE_DATASETS["ssvep"] = dict(
     archive_name="ssvep_example_data.zip",
     hash="md5:af866bbc0f921114ac9d683494fe87d6",
-    url="https://osf.io/download/z8h6k?version=5",
+    url="https://github.com/mne-tools/mne-data/releases/download/ssvep-5/ssvep_example_data.zip",
     folder_name="ssvep-example-data",
     config_key="MNE_DATASETS_SSVEP_PATH",
 )
@@ -282,7 +298,7 @@
 MNE_DATASETS["erp_core"] = dict(
     archive_name="MNE-ERP-CORE-data.tar.gz",
     hash="md5:5866c0d6213bd7ac97f254c776f6c4b1",
-    url="https://osf.io/download/rzgba?version=1",
+    url="https://github.com/mne-tools/mne-data/releases/download/erp_core-1/MNE-ERP-CORE-data.tar.gz",
     folder_name="MNE-ERP-CORE-data",
     config_key="MNE_DATASETS_ERP_CORE_PATH",
 )
@@ -290,7 +306,7 @@
 MNE_DATASETS["epilepsy_ecog"] = dict(
     archive_name="MNE-epilepsy-ecog-data.tar.gz",
     hash="md5:ffb139174afa0f71ec98adbbb1729dea",
-    url="https://osf.io/download/z4epq?version=1",
+    url="https://github.com/mne-tools/mne-data/releases/download/epilepsy_ecog-1/MNE-epilepsy-ecog-data.tar.gz",
     folder_name="MNE-epilepsy-ecog-data",
     config_key="MNE_DATASETS_EPILEPSY_ECOG_PATH",
 )
@@ -299,7 +315,7 @@
 MNE_DATASETS["fieldtrip_cmc"] = dict(
     archive_name="SubjectCMC.zip",
     hash="md5:6f9fd6520f9a66e20994423808d2528c",
-    url="https://osf.io/download/j9b6s?version=1",
+    url="https://github.com/mne-tools/mne-data/releases/download/fieldtrip_cmc-1/SubjectCMC.zip",
     folder_name="MNE-fieldtrip_cmc-data",
     config_key="MNE_DATASETS_FIELDTRIP_CMC_PATH",
 )
@@ -308,28 +324,28 @@
 MNE_DATASETS["bst_auditory"] = dict(
     archive_name="bst_auditory.tar.gz",
     hash="md5:fa371a889a5688258896bfa29dd1700b",
-    url="https://osf.io/download/5t9n8?version=1",
+    url="https://github.com/mne-tools/mne-data/releases/download/bst_auditory-1/bst_auditory.tar.gz",
     folder_name="MNE-brainstorm-data",
     config_key="MNE_DATASETS_BRAINSTORM_PATH",
 )
 MNE_DATASETS["bst_phantom_ctf"] = dict(
     archive_name="bst_phantom_ctf.tar.gz",
     hash="md5:80819cb7f5b92d1a5289db3fb6acb33c",
-    url="https://osf.io/download/sxr8y?version=1",
+    url="https://github.com/mne-tools/mne-data/releases/download/bst_phantom_ctf-1/bst_phantom_ctf.tar.gz",
     folder_name="MNE-brainstorm-data",
     config_key="MNE_DATASETS_BRAINSTORM_PATH",
 )
 MNE_DATASETS["bst_phantom_elekta"] = dict(
     archive_name="bst_phantom_elekta.tar.gz",
     hash="md5:1badccbe17998d18cc373526e86a7aaf",
-    url="https://osf.io/download/dpcku?version=1",
+    url="https://github.com/mne-tools/mne-data/releases/download/bst_phantom_elekta-1/bst_phantom_elekta.tar.gz",
     folder_name="MNE-brainstorm-data",
     config_key="MNE_DATASETS_BRAINSTORM_PATH",
 )
 MNE_DATASETS["bst_raw"] = dict(
     archive_name="bst_raw.tar.gz",
     hash="md5:fa2efaaec3f3d462b319bc24898f440c",
-    url="https://osf.io/download/9675n?version=2",
+    url="https://github.com/mne-tools/mne-data/releases/download/bst_raw-2/bst_raw.tar.gz",
     folder_name="MNE-brainstorm-data",
     config_key="MNE_DATASETS_BRAINSTORM_PATH",
 )
@@ -355,7 +371,7 @@
     # Zenodo can be slow, so we use the OSF mirror
     # url=('https://zenodo.org/record/3523071/files/'
     #      'hf_sef_evoked.tar.gz'),
-    url="https://osf.io/download/25f8d?version=2",
+    url="https://github.com/mne-tools/mne-data/releases/download/hf_sef_evoked-2/hf_sef_evoked.tar.gz",
     folder_name="hf_sef",
     config_key="MNE_DATASETS_HF_SEF_PATH",
 )
@@ -373,7 +389,9 @@
 MNE_DATASETS["eyelink"] = dict(
     archive_name="MNE-eyelink-data.zip",
     hash="md5:68a6323ef17d655f1a659c3290ee1c3f",
-    url=("https://osf.io/download/xsu4g?version=1"),
+    url=(
+        "https://github.com/mne-tools/mne-data/releases/download/eyelink-1/MNE-eyelink-data.zip"
+    ),
     folder_name="MNE-eyelink-data",
     config_key="MNE_DATASETS_EYELINK_PATH",
 )
diff --git a/mne/datasets/utils.py b/mne/datasets/utils.py
index c9b910a58e4..26090edee0b 100644
--- a/mne/datasets/utils.py
+++ b/mne/datasets/utils.py
@@ -255,9 +255,9 @@ def _download_mne_dataset(
     # handle case of multiple sub-datasets with different urls
     if name == "visual_92_categories":
         dataset_params = []
-        for name in ["visual_92_categories_1", "visual_92_categories_2"]:
-            this_dataset = MNE_DATASETS[name]
-            this_dataset["dataset_name"] = name
+        for part in sorted(key for key in MNE_DATASETS if key.startswith(f"{name}_")):
+            this_dataset = MNE_DATASETS[part]
+            this_dataset["dataset_name"] = part
             dataset_params.append(this_dataset)
 
     return cast(
@@ -444,7 +444,10 @@ def fetch_aparc_sub_parcellation(subjects_dir=None, verbose=None):
 
     subjects_dir = get_subjects_dir(subjects_dir, raise_error=True)
     destination = subjects_dir / "fsaverage" / "label"
-    urls = dict(lh="https://osf.io/download/p92yb", rh="https://osf.io/download/4kxny")
+    urls = dict(
+        lh="https://github.com/mne-tools/mne-data/releases/download/hcp_aparc_sub-1/lh.aparc_sub.annot",
+        rh="https://github.com/mne-tools/mne-data/releases/download/hcp_aparc_sub-1/rh.aparc_sub.annot",
+    )
     hashes = dict(
         lh="9e4d8d6b90242b7e4b0145353436ef77", rh="dd6464db8e7762d969fc1d8087cd211b"
     )
diff --git a/mne/viz/backends/_jupyterlite.py b/mne/viz/backends/_jupyterlite.py
index 74aba331ff7..39651556525 100644
--- a/mne/viz/backends/_jupyterlite.py
+++ b/mne/viz/backends/_jupyterlite.py
@@ -40,6 +40,8 @@ def setup_notebook(data_path="/tmp/mne_data"):
         Where fetched data files are written; ``MNE_DATA`` is set to it.
     """
     global _base, _data_root
+    if _data_root is not None:  # the cell ran again: the wrappers below would
+        return  # otherwise wrap their own wrapped selves and recurse
     import js  # only exists inside Pyodide
 
     # The docs serve the data next to the pages (/mne_data/, via
diff --git a/mne/viz/backends/tests/test_renderer.py b/mne/viz/backends/tests/test_renderer.py
index 75af51ee5e0..61c846e62f9 100644
--- a/mne/viz/backends/tests/test_renderer.py
+++ b/mne/viz/backends/tests/test_renderer.py
@@ -4,6 +4,7 @@
 
 import os
 import platform
+import subprocess
 import sys
 from contextlib import nullcontext
 
@@ -15,7 +16,6 @@
 import mne
 from mne.datasets import testing
 from mne.transforms import quat_to_rot, rot_to_quat
-from mne.utils import run_subprocess
 from mne.viz import Figure3D, get_3d_backend, set_3d_backend
 from mne.viz.backends._utils import ALLOWED_QUIVER_MODES
 from mne.viz.backends.renderer import _get_renderer
@@ -299,7 +299,8 @@ def test_renderer(renderer, monkeypatch):
         f"assert backend != 'jupyterlite_notebook' or 'vtk' not in sys.modules",
     ]
     monkeypatch.setenv("MNE_3D_BACKEND", backend)
-    run_subprocess(cmd)
+    proc = subprocess.run(cmd, capture_output=True, text=True, timeout=60)
+    assert proc.returncode == 0, proc.stderr
 
 
 def test_set_3d_backend_bad(monkeypatch, tmp_path):
@@ -588,6 +589,10 @@ def send(self):
 from mne.viz.backends._jupyterlite import setup_notebook
 
 setup_notebook(str(root))
+setup_notebook(str(root))  # running the cell twice must not wrap the wrappers
+from mne.viz.backends import _jupyterlite
+
+assert _jupyterlite._orig["read_raw_kit"] is not mne.io.read_raw_kit
 assert mne.viz.get_3d_backend() == "jupyterlite_notebook"
 assert mne.datasets.sample.data_path() == root / "MNE-sample-data"
 data = root / "MNE-testing-data"
@@ -622,4 +627,5 @@ def test_lite_setup_notebook(renderer_lite, tmp_path):
         )
     )
     args = [sys.executable, str(script), str(tmp_path / "mne_data"), str(_data_path)]
-    run_subprocess(args, env=env)
+    proc = subprocess.run(args, capture_output=True, text=True, env=env, timeout=60)
+    assert proc.returncode == 0, proc.stderr
diff --git a/pyproject.toml b/pyproject.toml
index 91ca7ed19a3..2fd89b7d710 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -16,6 +16,9 @@ doc = [
   # the two resolve together. Below either, the browser drops to Pyodide 0.29
   # and its matplotlib 3.8.4, a minor under the 3.9 MNE declares.
   "jupyterlite-pyodide-kernel >= 0.8",
+  # [lock] brings pyodide-lock and uv for jupyter_lite_config.py; pyodide-lock
+  # needs 3.12, which every docs build has
+  "jupyterlite-pyodide-kernel[lock] >= 0.8; python_version >= '3.12'",
   "jupyterlite-sphinx >= 0.23",
   "memory_profiler >= 0.16",
   "mne-bids",
@@ -44,6 +47,21 @@ doc = [
   "sphinxcontrib-youtube",
 ]
 doc-full = ["rpy2", { include-group = "doc" }]
+# Packages installed into the browser Pyodide kernel for JupyterLite notebooks;
+# unpinned, since Pyodide's curated version wins where it has one and the rest
+# resolve to the latest release (see doc/sphinxext/jupyterlite_lock_specs.py)
+jupyterlite = [
+  "joblib",
+  "mffpy",
+  "mne-connectivity",
+  "nibabel",
+  "pandas",
+  "python-picard",
+  "pyvista-js",
+  "pyxdf",
+  "scikit-learn",
+  "seaborn",
+]
 # Dependencies in a separate group for uv lockfile generation, currently only used for
 # the 'old' environment CI test run
 lockfile_extras = [