Open-Shell was forked from Classic Shell which was found by Ivo Beltchev and halted development later, announced here.

Classic Shell website: http://www.classicshell.net/
Mirror of Classic Shell website: https://coddec.github.io/Classic-Shell/www.classicshell.net/

Classic Shell forum: http://www.classicshell.net/forum/
Mirror of Classic Shell forum: https://coddec.github.io/Classic-Shell/www.classicshell.net/forum/index.html

Original Source Code by Ivo: https://sourceforge.net/projects/classicshell/

Fork of original Source Code on GitHub: https://github.com/coddec/Classic-Shell