Preset metadata is all data which describes a preset, but does not contain the preset data itself.
Metadata consists of:
Audio Preview Note
In terms of the NKS format, the plugin is usually not aware of the metadata and is only used for Maschine/Komplete Kontrol to organize presets.
A preset parser is a module which knows how to extract preset information for a specific plugin, and converts the presets into a generic format which can then be used to load the data into the plugin, or to generate an NKS file.
Example for Thorn by Dmitry Sches
PresetMagician finds a new plugin with the plugin ID 1416122947. It then asks all Preset Parser modules: "Hey, can someone handle the plugin with the ID 1416122947?". The Preset Parser "DmitrySches_Thorn" would respond with "Yes, I can!". It also knows that the presets are stored under Documents\Dmitry Sches\Thorn\Plug-In Presets and which exact format they're in.
It then converts all presets into a format which is used to send preset data from your DAW to the plugin, which then can be used by PresetMagician to generate NKS files.
Types / Characteristics
A type defines the category of a preset. Each type can have a main type and a sub-type. For example, the main type could be "Bass", and the sub-type could be "Acoustic", resulting in a complete type of "Bass > Acoustic".
A characteristic defines how the preset sounds. Typical characteristics are "Arpeggiated", "Soft", "Hard" etc.
Characteristics were called "Mode" in previous versions of PresetMagician, since Native Instruments used the term "Mode" instead of "Characteristic" until early 2019.