This property defines the Unicodes which belongs to Phags pa block
Characters like ꡀ,ꡁ,ꡂ, etc. are listed under Phags pa Block.
57 Characters are present in Phags pa Block starting with the Unicode point U+A840 that represents the character ꡀ.
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.