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

ase-core
3.23.0b1.post2

This version was deleted from PyPI around 2023-11-04. Installing fails with:
$ pip3 install ase-core==3.23.0b1.post2 ERROR: Could not find a version that satisfies the requirement ase-core==3.23.0b1.post2
View other deleted versions of ase-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/2023-11-03/ \ ase-core==3.23.0b1.post2
Sign up for StableBuild to get an API key (it's free and takes <60 seconds!)

Or, download files manually

And install manually via pip:
ase_core-3.23.0b1.post2-py3-none-any.whl (2.2MB)