/System/Library/Frameworks/CoreMediaIO.framework/Versions/A/Resources/iOSScreenCapture.plugin/Contents/Resources/iOSScreenCaptureAssistant iOSScreenCaptureAssistant is used by the CoreMediaIO Device Abstraction Layer Plug-In that provides audio/video capture from iOS devices using AVFoundation Capture APIs. The process allows multiple applications to simultaneously capture from the same iOS device.
The binary is a part of CoreMediaIO public framework.