So originally there is a wifi/bluetooth card in this space and it's small. I pretty sure this is a mini pcie port but I dome seem to find any ssd's small enough that looks like it will fit. I did get a ssd but it doesn't fit because it seems to be m.2 format.
This is also a Acer e5 523 Motherboard
Pictures of WIFI card, SSD, and Motherboard
View: https://imgur.com/a/plI0F0V
This is also a Acer e5 523 Motherboard
Pictures of WIFI card, SSD, and Motherboard
View: https://imgur.com/a/plI0F0V