> Why doesn't it work without REFERER headers?
Don't know. I just spotted that it's the only meaningful difference I had in my traffic between visiting with Firefox and with Chromium. IIRC, it's the fetching of the capture timestamps that fails when the Referer header is missing.
> I haven't changed any settings from the Firefox default
You might have forgotten like I did once.
> and allowing it breaks links to jwz's site.
Do you mean this one?
Seems to be working fine for me with the Referer header enabled. Maybe it was a temporary glitch?