You're looking at StableBuild's Deleted PyPI mirror - where we index all deleted packages from the Python package registry.
telethon2 was reported malicious
OSV:MAL-2023-8369 - Malicious code in telethon2 (PyPI)

telethon2
1.30.3

This version was deleted from PyPI around 2023-09-26. Installing fails with:
$ pip3 install telethon2==1.30.3 ERROR: Could not find a version that satisfies the requirement telethon2==1.30.3
View other deleted versions of telethon2

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/2023-09-25/ \ telethon2==1.30.3
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:
telethon2-1.30.3.tar.gz (540.3KB)