Source for both the documentation and the TeX macro
files. If you want to extract the macro files from it,
execute etex xint.dtx. If you want then to build
the PDF documentation, execute make xint.pdf with
the help of provided Makefile, or run latex three
times on file xint.tex which was extracted in
first step, then execute dvipdfmx xint.dvi. The
file xint.pdf will contain both the user manual
and the commented source code.
This is essentially the same file as served at the CTAN site. Currently (1.4o) it differs from it by some added installation instructions.
Change log since 2013 (in HTML format); for the serious user.
Markdown source of CHANGES.html.