U+042C Cyrillic Capital Letter Soft Sign

The Wikipedia has the following information about this codepoint:

The soft sign (Ь ь; italics: Ь ь) is a letter in the Cyrillic script that is used in various Slavic languages. In Old Church Slavonic, it represented a short or reduced front vowel. However, over time, the specific vowel sound it denoted was largely eliminated and merged with other vowel sounds.

In most contemporary Slavic Cyrillic writing systems, such as those used in East Slavic languages (Russian, Ukrainian, Belarusian) and Church Slavic, the soft sign does not represent a distinct sound on its own. Instead, it serves as an indicator of palatalization of the preceding consonant. In the Bulgarian language, it is only used to mark the palatalization of the preceding consonant when in front of the letter o, causing the combination ьо (/ʲo/). An example of this is the word гьол (/gʲol/).

Palatalization is a linguistic process in which the middle of the tongue moves closer to the hard palate while pronouncing a consonant. It affects the pronunciation of the preceding consonant by giving it a palatal quality or causing it to become a palatal consonant. The soft sign acts as a visual marker to show that the consonant before it is palatalized.

For example, in Russian, the soft sign is often used after consonants to indicate palatalization. It affects the pronunciation of the preceding consonant and can change the sound of words. The specific effect varies depending on the consonant it follows. In other Slavic languages where the soft sign is used, a similar palatalization function is observed.

It may also be used as a superscript. (^ь)