This property defines the Unicodes which are Modifier Letters
Characters like ʰ,ʱ,ʲ, etc. are listed under Modifier Letter General Category.
397 Characters are present in Modifier Letter General Category starting with the Unicode point U+02B0 that represents the character ʰ.
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.