U+1F9F "ᾟ" Greek Capital Letter Eta with Dasia and Perispomeni and Prosgegrammeni Unicode Character

U+1F9F "ᾟ" Greek Capital Letter Eta with Dasia and Perispomeni and Prosgegrammeni is a highly specific and rare polytonic Greek letter used in ancient Greek textual scholarship, combining three diacritical marks. The dasia indicates a rough breathing sound, the perispomeni marks a circumflex accent over the long vowel eta, and the prosgegrammeni is a small iota subscript written alongside the capital letter, which historically represents a long vowel followed by a silent iota in diphthongs. This character appears only in critically edited editions of ancient Greek texts, such as those of classical authors or the Greek New Testament, where it encodes precise phonological and orthographic details that are essential for accurate reading and interpretation of older manuscripts.