Dark.Fail is a dual stack (clearnet + .onion) website whose stated purpose is “to compile a list of ‘official’ .onion links to serve as an anti phishing resource”.
To aid in their (and everyone’s) ability to confirm if a given .onion mirror is legitimate or not the Dark.Fail website has proposed the “Onion Mirror Guidelines”.
This blog post discusses the OMG and Ablative’s OMG Ansible role that is available on Ansible Galaxy.