Set up redirect to new CGI script name

htdocs/.htaccess

 Options +ExecCGI
+AddHandler cgi-script .py
 <FilesMatch "^-$">
   SetHandler cgi-script
 </FilesMatch>

htdocs/visualizer.py

+#!/usr/bin/env python3
+"""Redirect to the new CGI script name, "-"."""
+
+import os
+from pathlib import PurePosixPath
+
+request_script = PurePosixPath(os.getenv('SCRIPT_NAME'))
+request_uri = PurePosixPath(os.getenv('REQUEST_URI'))
+relative = request_uri.relative_to(request_script)
+target_script = request_script.with_name('-')
+target = target_script / relative
+
+print('Status: 308 Permanent Redirect')
+print(f'Location: {target}')
+print()