This property defines the Decomposition Type of the Unicodes as Narrow Presentation Form
Characters like 。,「,」, etc. are listed under Narrow Presentation Form Decomposition Type.
122 Characters are present in Narrow Presentation Form Decomposition Type starting with the Unicode point U+FF61 that represents the character 。.
Currently, as per latest version 15.0.0, Unicode supports 18 number of Decomposition Type. Here are a few examples - Canonical Decomposition,Compatibility,Enclosing Mark, etc.