Nusach of Aleinu

These two Nuscho'os are old Nusho'os, according to the one Nusach one says ומושב יקרו every Oleinu (both on weekdays and on Musaf of Yomim Noroim), and according to the other Nusach וכסא כבודו is always said. Minhag Frankfurt was to make a compromise between the Minhogim, and to say ומושב יקרו the whole year, and וכסא כבודו on Musaf Yomim Noroim.

Michael FRBSH