U+0449 Cyrillic Small Letter Shcha

The Wikipedia has the following information about this codepoint:

Shcha (Щ щ; italics: Щ щ), Shta, Scha, Šče or Sha with descender is a letter of the Cyrillic script. In Russian, it represents the long voiceless alveolo-palatal fricative /ɕː/, similar to the pronunciation of ⟨sh⟩ in Welsh-sheep. In Ukrainian and Rusyn, it represents the consonant cluster /ʃt͡ʃ/, something like cash-chest. In Bulgarian, it represents the consonant cluster /ʃt/. Most other non-Slavic languages written in Cyrillic use this letter to spell the few loanwords that use it or foreign names; it is usually pronounced /ʃ/, an approximation of the Russian pronunciation of the letter, and is often omitted when teaching those languages.

In English, Russian Shcha is romanized as ⟨shch⟩, ⟨ŝ⟩, ⟨šč⟩ (with háčeks) or occasionally as ⟨sch⟩, all reflecting the historical Russian pronunciation of the letter (as a combined Ш and Ч). English-speaking learners of Russian are often instructed to pronounce it in this way although it is no longer the standard pronunciation in Russian (it still is in Ukrainian and Rusyn, as above). The letter Щ in Russian and Ukrainian corresponds to ШЧ in related words in Belarusian.