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

fsleyes
0.12.3

This version was deleted from PyPI around 2024-06-27. Installing fails with:
$ pip3 install fsleyes==0.12.3 ERROR: Could not find a version that satisfies the requirement fsleyes==0.12.3
View other deleted versions of fsleyes

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/2024-06-26/ \ fsleyes==0.12.3
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Or, download files manually

And install manually via pip:
fsleyes-0.12.3-py2.py3-none-any.whl (37.4MB)
fsleyes-0.12.3.tar.gz (49.6MB)