• URL: https://nodejs.org/en/about/
• Browser version: any
• Operating system: any

if you go to https://nodejs.org/en/about/, and click the link for Blocking vs Non-Blocking, it takes you to this URL: https://github.com/nodejs/node/blob/master/doc/topics/blocking-vs-non-blocking.md

which is a 404.