I'm +1 on giving this another go.

maintain the shell if it's added and establish some relevant automations towards its upkeep.

What is the expected maintenance / upkeep?

I'd like to propose reinstating this shell for the website (either on the same page, or elsewhere

Getting Started seems to be a natural place to me.

I'm +1 on giving this another go.

Thanks, @rhshadrach! I'll put together a PR to add it back, and I'm happy to take the discussion forward either there or here.

maintain the shell if it's added and establish some relevant automations towards its upkeep.

What is the expected maintenance / upkeep?

Here are my points on this:

• If we want the shell to always host the latest stable version of pandas, we need to ensure that the emscripten job in these lines:

  pandas/.github/workflows/unit-tests.yml

  Lines 414 to 471 in 5efac82

  	emscripten:
  	# Note: the Python version, Emscripten toolchain version are determined
  	# by the Pyodide version. The appropriate versions can be found in the
  	# Pyodide repodata.json "info" field, or in the Makefile.envs file:
  	# https://github.com/pyodide/pyodide/blob/stable/Makefile.envs#L2
  	# The Node.js version can be determined via Pyodide:
  	# https://pyodide.org/en/stable/usage/index.html#node-js
  	name: Pyodide build
  	runs-on: ubuntu-22.04
  	concurrency:
  	# https://github.community/t/concurrecy-not-work-for-push/183068/7
  	group: ${{ github.event_name == 'push' && github.run_number || github.ref }}-wasm
  	cancel-in-progress: true
  	steps:
  	- name: Checkout pandas Repo
  	uses: actions/checkout@v4
  	with:
  	fetch-depth: 0
  	- name: Set up Python for Pyodide
  	id: setup-python
  	uses: actions/setup-python@v5
  	with:
  	python-version: '3.11.3'
  	- name: Set up Emscripten toolchain
  	uses: mymindstorm/setup-emsdk@v14
  	with:
  	version: '3.1.46'
  	actions-cache-folder: emsdk-cache
  	- name: Install pyodide-build
  	run: pip install "pyodide-build==0.25.1"
  	- name: Build pandas for Pyodide
  	run: |
  	pyodide build
  	- name: Set up Node.js
  	uses: actions/setup-node@v4
  	with:
  	node-version: '18'
  	- name: Set up Pyodide virtual environment
  	run: |
  	pyodide venv .venv-pyodide
  	source .venv-pyodide/bin/activate
  	pip install dist/*.whl
  	- name: Test pandas for Pyodide
  	env:
  	PANDAS_CI: 1
  	run: |
  	source .venv-pyodide/bin/activate
  	pip install pytest hypothesis
  	# do not import pandas from the checked out repo
  	cd ..
  	python -c 'import pandas as pd; pd.test(extra_args=["-m not clipboard and not single_cpu and not slow and not network and not db"])'

  is here to stay, and that pandas continues to build WASM wheels in that manner. That said, I've just noticed that said job builds WASM wheels against an older version of Pyodide for some reason, so I'll bump it in a separate PR right now.
• Currently, the version of jupyterlite-pyodide-kernel controls the Pyodide version (0.27.1 right now), and the Pyodide version controls the versions of packages built with it, including pandas. Here's a list of available packages at the moment: https://pyodide.org/en/stable/usage/packages-in-pyodide.html. With Pyodide 0.28, we have been working on unvendoring the recipes from the Pyodide runtime (RFC Plans for unvendoring package recipes pyodide/pyodide#4918). Once done, we likely won't have this constraint later this year.
• Therefore, the required maintenance right now would be to ensure that the jupyterlite-pyodide-kernel version is pinned and updated from time to time, and that the JupyterLite deployment jupyter lite build succeeds.
• However, it is also possible to just rely on an external deployment (https://github.com/jupyterlite/demo), which means that there is less control over the pandas version and lesser customizability but more convenience. It also means that the build size for uploading on GitHub Pages will be larger, as source maps are enabled with that deployment, which means higher bandwidth usage. I've asked about it in Disable source maps for the deployment from this repository? jupyterlite/demo#151.
• I would consider that it is okay if the pandas version is a bit outdated, as this would only be a REPL that can serve basic functionality for pandas for newcomers, as they won't need access to cutting-edge features with the nightlies. However, we have also been working on having an appropriate place for nightly WASM wheels (which pandas already uploads to Anaconda.org via BLD, CI: Use cibuildwheel to build Emscripten/Pyodide wheels, push nightlies to Anaconda.org #58647) for use in the docs, so a "dev" REPL is also possible to add (xref A "dev" version of the REPL sympy/live#28 for a similar need for SymPy).

Short answer: we can either build a custom deployment + have to update the Pyodide kernel from time to time (or keep it unpinned if we don't want to update it), or use a different deployment elsewhere with less control over the pandas version and other JupyterLite-specific configurations. The previous state of the terminal in the older PRs had a custom deployment, so I'll keep that here for now.