CL-HTML-DIFF is copyright John Wiseman and is covered by the MIT license.
CL-HTML-DIFF uses CL-DIFFLIB.
Just because it's small doesn't mean it shouldn't be ASDF-INSTALLable:
ASDF-install package (obsolete) http://lemonodor.com/code/cl-html-diff_0.1.tar.gz
Topics: HTML HTML parser