If you are researching this topic for legitimate purposes (e.g., cybersecurity analysis, malware research, or academic study), I can help you structure a about risky download-assistant extensions. You would then need to obtain the actual extension file (e.g., via a controlled, offline, sandboxed environment) and analyze it using standard malware-analysis tools.
rather than being available on the official Chrome Web Store. Safety and Alternatives filecr assistant chrome extension free