seaborn was listed among the Pyodide distribution packages, but it is not part of that distribution, so the build wrote no wheel for it. Since seaborn is on the code interpreter's package list, it was quietly downloaded from pypi.org in the user's browser instead, which is what bundling the wheels is meant to avoid. It now takes the PyPI wheel path, like openpyxl.
The code editor's Format button was broken for non-admin users, with or without internet, because black's bundled lock entry declared no dependencies and the hand-written list next to the caller was missing packaging. black's dependencies are now declared in the lock, so that list goes back to black alone and every future caller gets them too.
Both of these shipped unnoticed because nothing checked that a listed package produced a wheel. The build now fails when one did not, naming it.
Verified offline with the network cut at undici's dispatcher: seaborn, black, the Excel roundtrip and the other listed packages all install from the bundled wheels, and a deleted wheel, a missing lock entry or a non-canonical key each fail the build.
Fixes#30145
openpyxl has been listed as a Pyodide package since March, but it is not part of the Pyodide distribution, so the build never wrote a wheel for it and never warned about it. In the browser code interpreter every Excel operation failed with ModuleNotFoundError: import openpyxl, pd.read_excel() and DataFrame.to_excel() alike.
It now takes the PyPI wheel path together with its dependency et-xmlfile, and the code interpreter installs it when a snippet imports openpyxl or calls pandas' Excel helpers, which need it without importing it by name.
Injected lock entries are now keyed by the canonical dashed package name, the only spelling pyodide resolves them by. As a side effect black's mypy-extensions now resolves from the bundled wheel too, so formatting Python in the editor no longer reaches out to PyPI at runtime.
Verified offline against a built static/pyodide with every network call blocked: a to_excel then read_excel roundtrip loads openpyxl and et-xmlfile from the local directory and returns the frame.
Fixes#30130
