When RD-D is installed, the program supplies you with a named palette of 173 colours in 2 forms, "HSL" and "Reduced". The HSL palette form makes full use of the available HSL values to accurately define the 173 colours offered. The Reduced palette form does not make full use of the available HSL ranges, but instead limits the values used in order to produce approximate colours. This palette in 2 forms is known as the "default" palette, in other words it is the palette you get if you do not specify any other. If you want to create your own palette, you can do this using the options described in the Advanced section.
The default palette resides in the program folder, in the sub-folder "colours" and also in the sub-folder "colours default". Even if you substitute the "colours" sub-folder with a different palette, you can always get the default palette back again because a copy remains in the "colours default" sub-folder (unless you delete it, of course).
If you examine the palette folder further, you will note that the colours are classified according to their most fundamental hues: "008 red", "060 yellow", etc. This emphasises the fact that the exotic names we often give to colours often do not reflect the hue itself. Sometimes, we do not even have a clear idea of what the fundamental hue really is. For example, "salmon" is classified as a kind of red, but dark and light salmon are best classifed as kinds of orange.
However, unless you are a graphics professional engaged in real picture re-constitution work using the reduced work template, you are unlikely to make great use of any kind of palette, including the default palette. To change the hue component of a flower in a photograph for example, only the fundamental hue name (red, yellow, etc.) is relevant. The other values for saturation and luminance are what you are preserving rather than substituting, so the named colour they may or may not actually define is of no practical interest. Nevertheless, it is certainly interesting and potentially useful to know that H=0 is shared by red, dark red, indian red, light coral, maroon, etc.
Named Colours - General
Choosing a Colour
What is WHITE/BLACK/GREY?
What is a Template?