This property defines the Decomposition Type of the Unicodes as Vertical Presentation Form
Characters like ゟ,ヿ,︐, etc. are listed under Vertical Presentation Form Decomposition Type.
35 Characters are present in Vertical Presentation Form Decomposition Type starting with the Unicode point U+309F that represents the character ゟ.
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.