WP6 - WordPerfect 6 Document
Due to the overwhelming popularity of WordPerfect 5.1, the WordPerfect Corporatioin sought to expand on the growing popularity of graphical user interface capabilities with WordPerfect 6 for DOS. This version incorporated a graphical view for documents so users could see what a document would look like when printed. This "Print Preview" mode enabled users to make corrections and design changes to a document before being printed.
While not a true "WYSIWYG" (what you see is what you get) interface, this was the precursor to much of what is known today as 'desktop publishing' as users were able to see a 'finished product' without wasting valuable paper and printer resources. Files saved in the .WP6 format were viewable or editable in WordPerfect 5.x and older WordPerfect files including the most popular .WP5 format were openable and modifiable in WordPerfect 6. This meant that WordPerfect users weren't forced to upgrade to WordPerfect 6 because of compatibility issues, leading to what amounted to be almost a 20 year life-cycle for WordPerfect 5 and WordPerfect 6 users.
Because of the popularity of WordPerfect, most third party word processing packages such as Microsoft Word had to build a combatibility factor into their software so .WP6 files could be supported. .WP6 files may be opened and edited by any version of WordPerfect 5.x and later as well as most third party word processing packages.