You're looking at StableBuild's Deleted PyPI mirror - where we index all deleted packages from the Python package registry.
pygments-richstyle was reported malicious
OSV:MAL-2025-191654 - Malicious code in pygments-richstyle (PyPI)

pygments-richstyle
1.0.0

This version was deleted from PyPI around 2025-11-01. Installing fails with:
$ pip3 install pygments-richstyle==1.0.0 ERROR: Could not find a version that satisfies the requirement pygments-richstyle==1.0.0
View other deleted versions of pygments-richstyle

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/2025-10-31/ \ pygments-richstyle==1.0.0
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:
pygments_richstyle-1.0.0-py3-none-manylinux1_x86_64.whl (1.2MB)
pygments_richstyle-1.0.0-py3-none-win_amd64.whl (1.4MB)
pygments_richstyle-1.0.0-py3-none-win32.whl (1.4MB)