Each letter use for different string purpose about this:
What are the explanations of the text string identifications?
* STR: Map texts
* STR_L: Large buttons (Large) as "objective input"
* STR_M: Mode button (right white to blue) and message texts
* STR_S: Description texts and small buttons below (Small; left black on white)
* STR_T: Title bar (except in BT menu, they are also as a description of the texts used)
* STR_X: Options (Selection or Chooses)