What is this wall covering type?
It is a spray on texture that was knocked down. Basically this is Sheetrock mud that was thinned down and put in a special gun to “spray splatter” the mud on the wall, when I do this I use lower air flow and larger nozzles to provide a larger “splatter” then go back with a wide 12-18” mud knife and knock it down that’s why it looks flat, in stead of an orange peal that is smaller spatter at higher airflow and left to dry, these are very common surface finishes, both are difficult to match but not impossible.