I am using Unity 2.2f1 as normal , but one day, i don't know why the visual studio had not exist the XR.ARFoundation, can't found it and can't debug any script, does any one can help to solve this problem? and when i changed to 2018.3.3 , it's ok, but export is black screen. please download the attachment, thanks ( Current Visual studio is 7.8.1 ) thank you very much