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

masster
0.5.10

This version was deleted from PyPI around 2025-09-22. Installing fails with:
$ pip3 install masster==0.5.10 ERROR: Could not find a version that satisfies the requirement masster==0.5.10
View other deleted versions of masster

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/2025-09-21/ \ masster==0.5.10
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:
masster-0.5.10-py3-none-any.whl (28.7MB)
masster-0.5.10.tar.gz (28.7MB)