Histone H3-like variant which exclusively replaces conventional H3 in the nucleosome core of centromeric chromatin at the inner plate of the kinetochore (PubMed:14716315, PubMed:16877494). Required for recruitment and assembly of kinetochore proteins, mitotic progression and chromosome segregation (Probable). Localizes in the kinetochore domain of centromeres. Belongs to the histone H3 family.