Well, I finally bought a Yuba Mundo. The owner's manual, seventeen pages joined with a staple, seems to consist mainly of warnings, with a few cautions thrown in, among which I thought the following particularly interesting:
"Never carry other riders or packages" !!!
"When braking always apply stronger braking pressure to the rear wheel . . . . If the front brake pressure . . . is applied too strongly or quickly, the bicycle may flip forward." I find it hard to believe that a bicycle as long and massive as the Mundo could flip.