This property defines the Unicodes which belongs to Yi Syllables block
Characters like ꀀ,ꀁ,ꀂ, etc. are listed under Yi Syllables Block.
1166 Characters are present in Yi Syllables Block starting with the Unicode point U+A000 that represents the character ꀀ.
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.