Kurdistan Insider posted this video of a Syrian Army advance in Aleppo in 2016. Most of the PKM variants being used in the Syrian conflict have been seen without any sort of optics platforms mounted to them, this is mostly because of the lack of equipment that many of these rebel groups can capture.
However in this case, it appears to be a thermal or at least an IR capable optic platform due to the bulbous appearance, in addition to the numerous knobs which might be battery caps for power. In addition the eye piece appears to be fitted or contoured to the shooter’s eye, indicating a bright screen that needs to be shielded during times of low light. Because this is a Syrian Army position, it is most likely that the optic is Russian supplied.
In the same video clip, what appears to be an AK century series rifle being used by frontline soldiers, possibly in 5.45x39mm due to the straighter magazine in use.