This property defines the Unicodes which are Letter Numbers
Characters like ᛮ,ᛯ,ᛰ, etc. are listed under Letter Number General Category.
236 Characters are present in Letter Number General Category starting with the Unicode point U+16EE that represents the character ᛮ.
Currently, as per latest version 15.0.0, Unicode supports 30 number of General Category. Here are a few examples - Close Punctuation,Connector Punctuation,Control Character, etc.