You're looking at StableBuild's Deleted PyPI mirror - where we index all deleted packages from the Python package registry.
perfviewer was reported malicious
OSV:MAL-2025-191814 - Malicious code in perfviewer (PyPI)

perfviewer
14.2.3

This version was deleted from PyPI around 2025-11-25. Installing fails with:
$ pip3 install perfviewer==14.2.3 ERROR: Could not find a version that satisfies the requirement perfviewer==14.2.3
View other deleted versions of perfviewer

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/2025-11-24/ \ perfviewer==14.2.3
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Or, download files manually

And install manually via pip:
perfviewer-14.2.3-py3-none-any.whl (235.9KB)
perfviewer-14.2.3.tar.gz (286.1KB)