Ibn Amir is the Syrian reader, and his reading is the recitation of Damascus under the Umayyads, which is to say of the capital of the caliphate at the height of its reach. He led the prayer at the great mosque of the city, and he died in 118 AH, making him the earliest of the seven readers by date of death and the one standing closest to the generation of the Companions.
Damascus had received one of the codices Uthman sent out, and the Syrian recitation carried a small number of differences in the consonantal skeleton itself, not merely in vocalisation, because the regional exemplars were not identical to one another in every letter. That is a fact the discipline states openly and has always stated openly. It is the reason a reading's home city is a substantive piece of information about it rather than biographical colour.
Ibn Amir's line runs through Damascene teachers to the Companions, and his reading is transmitted by Hisham ibn Ammar and Ibn Dhakwan, both of them men of the following century who served the same mosque. Like the Meccan reading it is now studied rather than recited by any settled population. The Syrian recitation lost its region during the centuries in which other lines spread and consolidated, and what survives of it survives because the discipline preserves chains whether or not anyone is currently using them.