The data was given to us by the Slovak Academy of Sciences (see https://wiki.openstreetmap.org/wiki/WikiProject_Slovakia/Sources#Geografick%C3%BD_%C3%BAstav_Slovenskej_akad%C3%A9mie_vied). I am not sure with what accuracy the boundaries were provided, but my guess is that it should closely follow the international boundaries, as there definitely are geomorphological areas that span international borders substantially, but we do not see that reflected in the dataset we received and imported.