8 reserved code points
72 code points
(80 code points)|Hangul Jamo Extended-B Wikipedia
Hangul Jamo Extended-B is a Unicode block containing positional (Choseong, Jungseong, and Jongseong) forms of archaic Hangul consonant and vowel clusters. They can be used to dynamically compose syllables that are not available as precomposed archaic Hangul syllables in Unicode containing sounds that have since merged phonetically with other sounds in modern pronunciation.