That’s correct… though it should be working here, we didn’t disable it
e.g. https://www.ietf.org/ and https://www.discourse.org/ and https://meta.discourse.org/ and The Long Earth - Wikipedia
or https://www.ietf.org and https://www.discourse.org and 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: some experimentation shows that only URLs with a non-blank path component are inline-oneboxed
e.g. https://www.discourse.org vs. https://www.discourse.org/ vs. https://www.discourse.org/buy vs. https://www.discourse.org/buy/
e.g. https://www.discourse.org vs. https://www.discourse.org/ vs. https://www.discourse.org/buy vs. https://www.discourse.org/buy/
EDIT: that’s not how it behaved on try 
