It should be compatible with Python 3, which is what distributions use these days.
Works well. Tested on Ubuntu 20.04: ✓ Redirect from HTTP to HTTPS ✓ Client launched with correct username and password ✓ Non-ascii username and password ✓ Pre-filled fields (via query string) ✓ Default redirection ✓ Custom redirection
Tested on Fedora 34 and it works just fine: ✓ Redirect from HTTP to HTTPS ✓ Client launched with correct username and password ✓ Non-ascii username and password ✓ Hexpassword (non-ascii utf-8 encoded, then hex encoded) ✓ Pre-filled fields (via query string) ✓ Default redirection ✓ Custom redirection