RTM tool = Real Time Modding tool
It allows you to modify a games / app's memory in real time with values that you send from a computer connected to the same LAN (your home network).
On another note... for anyone planning to risk modding online with HEN, its arguably safer to use a resigned SPRX plugin for CEX specifically made for your game.
The way that this guide is setup, if you press R2 + Square together, all syscalls will be disabled including the ones needed to keep PS3MAPI working. To have at least a less chance of a ban, you can try disabling all syscalls except the one needed for PS3MAPI to function if you REALLY need to use a RTM tool.