This property defines the Unicodes which belongs to CJK Unified Ideographs block
Characters like 一,丁,丂, etc. are listed under CJK Unified Ideographs Block.
20992 Characters are present in CJK Unified Ideographs Block starting with the Unicode point U+4E00 that represents the character 一.
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.