Those who endeavor to understand the inner workings of the LaTeX codebase only have pain and suffering awaiting them. For example, http://latex-project.org/svn

Those who endeavor to understand the inner workings of the LaTeX codebase only have pain and suffering awaiting them. For example, http://latex-project.org/svnroot/experimental/trunk/l3kernel/l3color.dtx http://latex-project.org/svnroot/experimental/trunk/l3kernel... or even http://latex-project.org/svnroot/experimental/trunk/l3kernel/l3prop.dtx http://latex-project.org/svnroot/experimental/trunk/l3kernel...