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

flaskz
1.6.5rc1

This version was deleted from PyPI around 2023-12-27. Installing fails with:
$ pip3 install flaskz==1.6.5rc1 ERROR: Could not find a version that satisfies the requirement flaskz==1.6.5rc1
View other deleted versions of flaskz

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/2023-12-25/ \ flaskz==1.6.5rc1
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:
flaskz-1.6.5rc1-py3-none-any.whl (53.5KB)
flaskz-1.6.5rc1.tar.gz (49.4KB)