QuarkXPress

QuarkXPress is a desktop publishing application.

Identifiers
Many file extensions have been reported: .qcd, .qct, .qpt, .qxd, .qxp, .qxl, .qxt, .qwd, .qwt, .qxb, .qxl. More research may be needed to sort this out.

Identification
Files have "" or "" at offset 2.

Software

 * QuarkXPress
 * Re-lab / OLE Toy - Appears to have some support for parsing the format

Links

 * QuarkXPress
 * QuarkXPress website
 * Planet Quark