This model represents a common C-terminal region shared by paramyxovirus-like RNA-dependent RNA polymerases (see pfam00946). Polymerase proteins described by these two models are often called L protein (large polymerase protein). Capping of mRNA requires RNA triphosphatase and guanylyl transferase activities, demonstrated for the rinderpest virus L protein and at least partially localized to the region of this model.
Jiyao W et al.(2023). "The conserved domain database in 2023.",