Facsimile Editions - Grove Music Online defines 'facsimile' as:
the “Name given to a genre of book publishing based on photo-mechanical printing techniques that attempts to recreate the appearance of an original handwritten manuscript or printed edition … It is important to note that facsimile editions are not fakes or forgeries. They are produced, conceived and used as tools for study or investigation by scholars, researchers, teachers and others who might not have access to the original material …”
Facsimile editions are generally not intended for use in performance, although they can be helpful in determining past performance practices.