You're looking at StableBuild's Deleted PyPI mirror - where we index all deleted packages from the Python package registry.

karellen-llvm-core
18.1.1.0.post44

This version was deleted from PyPI around 2024-05-19. Installing fails with:
$ pip3 install karellen-llvm-core==18.1.1.0.post44 ERROR: Could not find a version that satisfies the requirement karellen-llvm-core==18.1.1.0.post44
View other deleted versions of karellen-llvm-core

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/2024-05-18/ \ karellen-llvm-core==18.1.1.0.post44
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Or, download files manually

And install manually via pip:
karellen_llvm_core-18.1.1.0.post44-py3-none-manylinux2014_x86_64.whl (27.3MB)