It means that the audio thread is waiting for data. It's a diagnostic.
I've been meaning to ask you: In addition to the "w" icon, there is also a new icon where it is solid gray in the center instead of hollow with gray dots in the center. What's that one?
There used to be four possible icons, documented
here as:
No icon: Disk drives are spun down.
Icon with empty center: Drives are spinning up.
Icon with gray center: Drives are spun up.
Icon with bright center: Data is being read.
But now there appear to be six. I'm going to rewrite the FAQ entry as follows, but I don't know how to complete it:
No icon: Disk drives are spun down.
Icon with empty center: Drives are spinning up.
Icon with gray dots in center: Drives are spun up.
Icon with bright dots in center: Data is being read.
Icon with the letter W next to it: Audio thread is waiting for data (for diagnostic purposes).
Smaller icon with solid gray in center:
?????
Maybe I should get screen shots of these...