There are two city tables per country. The naming conventions are xxxCITY.ext where xxx is the 2- or 3-character country code and .ext is either len or ben. For example, the city tables for Austria are ATCITY.len and ATCITY.ben.
There are also two auxiliary city tables per country. The naming conventions for the xxxAUXCIT.ext table files are the same as the city tables. For example, the auxiliary city tables for Austria are ATAUXCIT.len and ATAUXCIT.ben.