This property defines the Unicodes which belongs to Avestan block
Characters like 𐬀,𐬁,𐬂, etc. are listed under Avestan Block.
62 Characters are present in Avestan Block starting with the Unicode point U+10B00 that represents the character 𐬀.
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.