It is found on the Cydia/Telesphoreo repository, and the author is Saurik.

How to SSH into your iPhone or iPadġ) If you do not already have it installed, install OpenSSH onto your device from Cydia. Installing OpenSSH on devices running iOS 9.3.3 or lower is however completely safe. They already include a different SSH client, and installing OpenSSH alongside it will cause issues. Please note, this procedure does not apply to the iOS 10 Yalu jailbreaks. This is a major security risk, and so everyone who has OpenSSH installed should follow this procedure. We will also go through how to change the default passwords on your device, because once you have installed OpenSSH, anyone can log in using the default passwords if you do not change them. In this guide we will show you how to use SSH to connect to your device from your computer.

The connection used to do this is called SSH, and is normally provided by the OpenSSH package (or an equivalent client such as Dropbear). For example, tihmstar’s Prometheus suite downgrades your device by sending commands to it from the computer on which it, and the files it uses, are stored. Sometimes it is necessary to connect to your mobile device from a computer, for troubleshooting purposes or to use a tool which runs from the computer.

Dropbear ssh for mac os x iphone 6