TraceFree is a simple xTension package for xAct. It is forked from HelloWorldxTension as an example of what needs to be changed to create a new package. This package serves as an example for the framework needed to create a package, and how to use xTension to extend the capabilities of xAct.
This directory should reside inside your xAct installation, at the same level as xCore, xTensor, etc. The directory tree should look like this:
xAct |-- ... |-- TraceFree | |-- Kernel | | +-- init.m | |-- TraceFree.m | |-- TraceFree.nb | +-- README.md (this file) |-- xTensor |-- ... (other xAct packages)