It does not need any third-party tools from Adobe or others.
It is released with a BSD-style license.
It can be downloaded with quicklisp.
The old CL-PDF home page: http://www.fractalconcept.com/asp/cl-pdf
A old version of the documentation can be found in cl-typesetting: cl-pdf-doc.pdf.
There are mailing lists and a code repository now. See home page for details.
CL-PDF is used by cl-typesetting, a Common Lisp typesetting engine.