An instance of opensource mediawiki is used as the popular Hidden Wiki.

http://rk56xqf2gjses2o2wop56qw4rlonaor33s7c6nyqc6xqndpmar47acyd.onion

This Hidden Wiki is specially created as a copy from old and outdated hidden wikis, and serves as a resource to provide real and original onion links. The Hidden Wiki is a dark web MediaWiki wiki operating as Tor hidden services that could be anonymously edited after registering on the site. The main page served as a directory of links to other .onion sites. 

The first Hidden Wiki was operated through the .onion pseudo top-level domain which can be accessed only by using Tor or a Tor gateway. Its main page provided a community-maintained link directory to other hidden services, including links claiming to offer money laundering, financial services, documents forgeries, contract killing, cyber-attacks for hire, contraband chemicals, and bomb making. The rest of the wiki was essentially uncensored as well and also offered links to sites hosting drug dealers.

http://rk56xqf2gjses2o2wop56qw4rlonaor33s7c6nyqc6xqndpmar47acyd.onion

http://rk56xqf2gjses2o2wop56qw4rlonaor33s7c6nyqc6xqndpmar47acyd.onion