I've searched this topic and I think it's not posted yet.
So this is to discuss on the meaning of the lyrics of ¡Tré! songs as we did with the songs of ¡Uno! in other topic.
To put my two cents, I read an interview where Billie said that X-kid is about a friend of them that committed suicide because he couldn't face that his youth was over. And I've heard rumors that says that 'Little boy named Train' is about a Billie's friend that was hermaphrodite or something like that, but I haven't seen them saying it. Also I feel curious about 'Dirty Rotten Bastards', there appear lot of references to old songs, but I can't figure out the whole meaning.