U+0476 Cyrillic Capital Letter Izhitsa with Double Grave Accent

The Wikipedia has the following information about this codepoint:

Izhitsa (Ѵ, ѵ; italics: Ѵ ѵ; OCS: ѷжица, Russian: ижица, Ukrainian: іжиця) is a letter of the early Cyrillic alphabet and several later alphabets, usually the last in the row. It originates from the Greek letter upsilon (Y, υ) and was used in words and names derived from or via the Greek language, such as кѵрилъ (kürilǔ, "Cyril", from Greek Κύριλλος) or флаѵии (flavii, "Flavius", from Greek Φλάυιος). It represented the sounds /i/ or /v/ as normal letters и and в, respectively. The Glagolitic alphabet has a corresponding letter with the name izhitsa as well (Ⱛ, ⱛ). Also, izhitsa in its standard form or, most often, in a tailed variant (similar to Latin "y") was part of a digraph оѵ/оу representing the sound /u/. The digraph is known as Cyrillic "uk", and today's Cyrillic letter u originates from its simplified form.

The letter's traditional name, izhitsa (ижица), is explained as a diminutive either of the word иго (igo, "yoke"), due to the letter's shape, or of иже (izhe, "which"), the name of the main Cyrillic and Glagolitic letters for the same sound, /i/.

The numeral value of Cyrillic izhitsa is 400. Glagolitic izhitsa has no numeral value. Church Slavonic editions printed in Russia use a tailed variant of the letter for the numeral purpose, whereas editions from Serbia or Romania (including books in the Romanian Cyrillic alphabet), as well as early printed books from Ukraine, prefer a basic form of the letter without the tail.