There are a several links in the documentation that lead to "Page not found" in github. It usually occurs when linking to a source file. The ones I see are:

Under "Export your issues into a supported format", the XML, JSON, and example links are all wrong. 

Under "Quality gate configuration", the QualityGateType link is wrong.

Under "Simple Pipeline configuration, the "step implementation" link is wrong.

Under "Advanced Pipeline configuration", the AnnotatedReport, and both "step implementation" links are wrong.