This property defines the Unicodes which belongs to Combining Diacritical Marks Supplement block
Characters like ᷀,᷁,᷂, etc. are listed under Combining Diacritical Marks Supplement Block.
64 Characters are present in Combining Diacritical Marks Supplement Block starting with the Unicode point U+1DC0 that represents the character ᷀.
Currently, as per latest version 15.0.0, Unicode supports 328 number of Block. Here are a few examples - Latin Extended E,Adlam,Aegean Numbers, etc.