This property defines the Unicodes which belongs to Hangul Jamo Extended B block
Characters like ힰ,ힱ,ힲ, etc. are listed under Hangul Jamo Extended B Block.
74 Characters are present in Hangul Jamo Extended B Block starting with the Unicode point U+D7B0 that represents the character ힰ.
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.