NRTDRV MAN EN SYNTAX PRESETTONE
From MSX MUSIC WIKI
Preset tone definition / Preset header definition
When you create a file called PRESET.MML in the same folder as NRTDRV.EXE, its contents are defined as presets.
It is possible to describe a tone definition and a header, it is convenient to define frequently used tones and headers. (Even if you write other contents, it will not be an error, but it will be ignored).
If the header is duplicated between the preset and the song data, the song data side description takes precedence.
