The documentation comes in two formats:
Documentations for single packages can be found in the directory doc/english/pdf as PDF files and in directory doc/english/html as HTML files. Names of the PDF files are simply <Name of Opt>.pdf, the HTML version can be found at <Name of Opt>/index.html.
There is also a version of the documentation available that describes all packages in a single document. It may be found as a separate package at www.fli4l.de. After unpacking the documentation the new position of the docs may be found there. The complete documentation my also be accessed directly at www.fli4l.de.