This addon extends the create_account.php page with a "Honeypot". This Honeypot is designed to help your site trap "bad actors" (spammers, bots) who automatically create accounts, in conjunction with other options such as a Maths Captcha.
If the Honeypot detects a bad actor, the create_account form will silently fail, leaving that bad actor to wonder what is going on.
In other words, this addon is designed to HELP stop your site being abused, by drive by spammer and idiots.
There are zero core code changes in this addon, which means you are guaranteed a simple installation!