Every image in the rdoc.css that use url has the wrong one. They end up pointing to `css/images/zoom.png` instead of `images/zoom.png`. Just open this page https://ruby.github.io/rdoc/RDoc/CodeObject.html on chrome and you can see in the console the spam of the failed GET queries. This fixes it. https://github.com/ruby/rdoc/commit/daf36f9894