U+1FCC "ῌ" Greek Capital Letter Eta with Prosgegrammeni Unicode Character

U+1FCC "ῌ" Greek Capital Letter Eta with Prosgegrammeni is a historic Greek typographic form representing the letter eta (Η) combined with a subscript iota, known as the "prosgegrammeni" or adscript iota, which appears as a small iota shape attached to the lower right of the capital letter. This character was used in ancient and medieval Greek texts to indicate a long vowel sound where an original iota had become silent or lost in pronunciation, functioning as a diacritical mark rather than a separate letter. It is distinct from the modern Greek lowercase iota subscript (used with vowels like ᾳ, ῃ, ῳ) but serves a similar grammatical role in denoting specific Greek verb forms or dative cases, and it is encoded separately for compatibility with historical writing systems and scholarly transcription of ancient manuscripts.