This property defines the Unicodes which belongs to Limbu block
Characters like ᤀ,ᤁ,ᤂ, etc. are listed under Limbu Block.
72 Characters are present in Limbu Block starting with the Unicode point U+1900 that represents the character ᤀ.
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.