Notifications: What does the PIPE icon mean in the status bar? (with image)

I just realized this today, and I have not installed any applications related to this Pipe icon. It simply flashes and disappears repeatedly, but if you press the status bar, there is no visible notification that you can verify.

I checked the running applications, I can not find any related application, I only have Messenger, Tasker, Spotify and other system applications. It seems that I could not find any detail through google either. I have already tried to restart.

Is there any way to find out this application? maybe through adb? I have root.enter the description of the image here