Ok, I looked at the WebRTC source code from the GitHub project, and there is no AppKit support, just UIKit. If you target a macOS app with macCatalyst, then any derived or subclassed UIView or UIKit-based view or controller subclassed view like RTCEAGLVideoView and RTCMTLVideoView will use the correct symbols. For macOS support using the swift package is going to call for a separate Xcode project targeting macCatalyst.
For example: UIView class type is UIKit only. To get this on macOS you will have to use a macCatalyst target.
open class RTCEAGLVideoView : UIView, RTCVideoRenderer {
weak open var delegate: RTCVideoViewDelegate?
public init(frame: CGRect, shader: RTCVideoViewShading)
public init(coder aDecoder: NSCoder, shader: RTCVideoViewShading)
/** @abstract Wrapped RTCVideoRotation, or nil.
*/
open var rotationOverride: NSValue?
}
