Scribus

Scribus is an open source desktop publishing application. It has a native Scribus Document format (SLA; SCD in older versions), among other native formats. It also supports many other DTP formats, vector graphics formats, and similar formats.

SLA format is based on XML.

Specifications

 * File Format Specification for Scribus 1.4

Links

 * Scribus website
 * Scribus wiki
 * List of Scribus file formats
 * Scribus
 * XML Processing of SLA Files