Ruby documentation URL redirects are not working at 100%.
Most do at least get to the new YARD class or module page at ruby.sketchup.com.
But the specific method anchors are not working, because the old docs used a different way of naming the method anchors.
Example, in this post: https://forums.sketchup.com/t/move-all-items-in-group-and-sub-groups-to-new-layer/11655/6?u=danrathbun
I give this link:http://www.sketchup.com/intl/en/developer/docs/ourdoc/layer#page_behavior
and it redirects to the class, because the real new link to the instance method is:http://ruby.sketchup.com/Sketchup/Layer.html#page_behavior-instance_method
Also note, that I have had a few not "get there" and give me 404 not found errors.