Isso mesmo… embora deva estar funcionando aqui, nós não o desativamos
por exemplo, https://www.ietf.org/ e https://www.discourse.org/ e https://meta.discourse.org/ e The Long Earth - Wikipedia
ou https://www.ietf.org e https://www.discourse.org e https://meta.discourse.org
[1] pry(main)> InlineOneboxer.lookup 'https://www.ietf.org/'
=> {:url=>"https://www.ietf.org/", :title=>"IETF | Internet Engineering Task Force"}
[2] pry(main)> InlineOneboxer.lookup 'https://www.discourse.org/'
=> {:url=>"https://www.discourse.org/",
:title=>"Discourse is the place to build civilized communities | Discourse - Civilized Discussion"}
[3] pry(main)> InlineOneboxer.lookup 'https://en.wikipedia.org/wiki/The_Long_Earth'
=> {:url=>"https://en.wikipedia.org/wiki/The_Long_Earth", :title=>"The Long Earth - Wikipedia"}
EDIT: algumas experimentações mostram que apenas URLs com um componente de caminho não em branco são inline-oneboxed
por exemplo, https://www.discourse.org vs. https://www.discourse.org/ vs. https://www.discourse.org/buy vs. https://www.discourse.org/buy/
por exemplo, https://www.discourse.org vs. https://www.discourse.org/ vs. https://www.discourse.org/buy vs. https://www.discourse.org/buy/
EDIT: não foi assim que se comportou em try 
