You're looking at StableBuild's Deleted PyPI mirror - where we index all deleted packages from the Python package registry.
msgspec-python313-pre was reported malicious
OSV:MAL-2025-2977 - Malicious code in msgspec-python313-pre (PyPI)

msgspec-python313-pre
0.19.1

This version was deleted from PyPI around 2024-12-30. Installing fails with:
$ pip3 install msgspec-python313-pre==0.19.1 ERROR: Could not find a version that satisfies the requirement msgspec-python313-pre==0.19.1
View other deleted versions of msgspec-python313-pre

Install through StableBuild

You can install this package from StableBuild's PyPI snapshots from before the version was deleted:
pip3 install \ -i https://YOUR_API_KEY.pypimirror.stablebuild.com/2024-12-29/ \ msgspec-python313-pre==0.19.1
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Or, download files manually

And install manually via pip:
msgspec_python313_pre-0.19.1-py3-none-any.whl (217.7KB)
msgspec_python313_pre-0.19.1.tar.gz (309.2KB)