Guidance for title designations

I couldn't find any guidance on the correct use of the different designations for title types.  For example, "le fidèle" (original title) also appears (incorrectly capitalized) as the Italian "short title".  The correct Italian complete title, "Le fidèle - Una vita al massimo" appears as an "imdb display title", but "Le Fidele" (also incorrectly capitalized) is also listed as a "complete title" for Italy.  What qualifies a "complete title" or an "imdb display title"?