My first project, since i have actually no access to an HP 260, is to write a program called hp260dir. This program is able to read .hpi archives produced by the site http://www.hpmuseum.net . It's similar to the HPDir utility from http://www.hp9845.net but the ouput reflect exactly what we should obtain with the CAT command on a HP250 / HP260.
The legacy source code is in the GitHub https://github.com/rlangmeier/hp260dir_2010_legacyÂ