No food and the music can vary from folk to whatever. It is really just a bar with a pub-like decor. Have you looked at the deck plans on the Royal Caribbean website? You can find the Navigator Of The Seas HERE. Select various decks at the upper left.
When I went on the Navigator in February 2008 I spent a lot of time in the Irish Pub. I love Ireland, and lucked out on our sailing they had a great Irish entertainer.