On the "Domenico Scarlatti: Sonates, Volume 10" edition of Scarlatti Sonata in F minor K.466 (obtainable from imslp), there are two occasions where the letter "G" is marked above a note, in bar 20 and 59 respectively:
What is the purpose of the letter "G" at that position? I observed that:
- The two instances are related, since the second section of the sonata is a development of the first section.
- The interval is an augmented octave.
- The upper note is executed as scored in all recordings, i.e. Ab on the first occasion and Db on the second.
- The score is written for the harpsichord.

