[1] = Hesychius. The headword, a commonplace single-word locative, is evidently quoted from somewhere.
2The point of the supplementary/explanatory sentence is to distinguish the plural AthenAI (*)aqh=nai) from the singular AthenE (*)aqh/nh). (Note, however, that Stephanus of Byzantium↗ listed both of them - and six others - as plural.)