Far to many "Full Scores" consist of only portions of the selected work. In Opera, that often means just some selected Arias, and perhaps the Overture. In this case, the term "full score" truly means Full Score. Every note is there, from the Overture to the final chord. Every line of recit is included, even those that are most often spoken rather than sung. In addition, the full libretto is given...in both Italian and German.
This version was completed by Georg Schünemann in Berlin in 1941! He cited the numerous "original" versions he used as references, even to the point of acknowledging that the sole copy of a particular printing was in Washington, and, sadly, not available to him at the time. He also supplies several pages of notes, identifying things that were "missing" from various versions or explaining which version he chose for a particular passage and why. As a study guide, for students of Mozart, students of opera, or students of orchestration this is an outstanding book, well made and certain to last a long time. It is unlikely anyone will produce anything "better."
For serious students it provides a good look at what Mozart wrote, and allows easy comparisons with versions produced today where some directors seem to feel that they can make "changes" and bill them as "improvements." In my opinion, Mozart knew exactly what he was doing, and "improvements" are seldom as good as the original...usually much worst. HINT: To a certain unconventional director: There's no silent angel in Mozart's work...for a good reason!