On September 8th the firm did take a tentative step back into the country: Motorola, its former handset unit, launched the first smartwatch supported by Google and powered by its operating system, Android, that understands Chinese voice commands.
摘自经济学人。划线部分的逗号后应该是定语从句,问题是这是非限制性定语从句吗?应该不是,那么逗号可以省略吗?