This property defines the Unicodes which belongs to Vai block
Characters like ꔀ,ꔁ,ꔂ, etc. are listed under Vai Block.
301 Characters are present in Vai Block starting with the Unicode point U+A500 that represents the character ꔀ.
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.