(related variations: sxi sti)

A StarOffice (version 6 and later) or OpenOffice Impress document (used for holding presentations -- the two use the same format); can be read on any machine with StarOffice or OpenOffice installed (available for for free for many platforms including WinTel boxes, Macs, and some types of UNIX boxes). The version with the "x" is an ordinary document; the version with the "t" is a template for building other documents.