It is a penetration testing tool that focuses on the web browser.
Best Tools For Penetration Testing
Browse 6 + Penetration Testing Tools

beef

Arachni
Web Application Security Scanner Framework

Awesome Penetration Testing
A collection of awesome penetration testing and offensive cybersecurity resources.

Pentest Bookmarkz
A collection of useful links for Pentesters
mitmproxy
It’s a free and open source interactive HTTPS proxy
Curl
command line tool and library for transferring data with URLs