No, TweakBox is not a jailbreak. It is a web-app, that install the TweakBox app icon on your iPhone. You can download and install Tweakbox to get 3rd-party apps on your device. You can also download apps that jailbreak your device. The Unc0ver app is a very popular option for that ...
however. Pigs can be so well trained to electric fencing that when we want to move them they will not go near a place that there USED to be electric fencing.