This property defines the Unicodes which belongs to International Phonetic Alphabet Extensions block
Characters like ɐ,ɑ,ɒ, etc. are listed under International Phonetic Alphabet Extensions Block.
96 Characters are present in International Phonetic Alphabet Extensions Block starting with the Unicode point U+0250 that represents the character ɐ.
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.