There is only one file type that uses the .WP6 extension:
WordPerfect 6 Document
Word processing document created by WordPerfect 6.x for DOS, the first version of WordPerfect to include a graphical editing mode, which displayed how the document would look when printed; may contain text styles such as bold, underlined, and italics, which were not possible in previous versions of the program.
WP6 files can be opened with Corel WordPerfect 6 or later.
Updated: October 18, 2010