B.1.2 How can I get plasT_eX to find my L^aT_eX packages?

There are two types of packages that can be loaded by plasT_eX: 1) native L^aT_eX packages, and 2) packages written entirely in Python. plasT_eX first looks for packages written in Python. Packages such as this are written specifically for plasT_eX and will yield better parsing performance as well as better looking output. Python-based packages are valid Python packages as well. So to load them, you must add the directory where your Python packages are to your PYTHONPATH environment variable. For more information about Python-based packages, see the section 4.3.

If you have a true L^aT_eX package, plasT_eX will try to locate it using the kpsewhich program just like L^aT_eX does.