This property defines the Unicodes which belongs to Miscellaneous Symbols and Arrows block
Characters like ⬀,⬁,⬂, etc. are listed under Miscellaneous Symbols and Arrows Block.
255 Characters are present in Miscellaneous Symbols and Arrows Block starting with the Unicode point U+2B00 that represents the character ⬀.
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.