For some instruments the pitch shown on the standard notation has an additional transposition. One example is the Guitar. Notes are shown 1 octave higher than they are on the piano. The following image shows a C4 for a piano and a guitar, and a C5 for the piano as comparison:
DisplayTranspositionPitch setting allows defining an additional pitch offset per track, that is then considered when displaying the music sheet.
This setting does not affect the playback of the instrument in any way. Despite the 2 different standard notations in the above example, they both play the same note height.
The transposition is defined as number of semitones and one value per track of the song can be defined.