That isn’t a typo. The Rootmaster Bustaurant is a vegan restaurant in an old bus, and from there a new word, "bustaurant", has been created. It is currently parked in Elys Yard off Brick Lane in London.
The lower deck has been converted into a kitchen with a takeaway hatch, whilst the upstairs now offers seating for 28 diners. The bus can also be hired for private parties, although you have to adhere to their strict vegan policy. Lentils, tofu and brown rice do feature heavily in their dishes, but many of them do sound pretty good. They also sell organic wines and beers.
For those of your interested in such matters, the bus is one of the later examples of the RML, number 2690 which entered into service with London Transport at Aldenham depot in September 1967 and was in service until 2004.
Further details of Rootmaster’s philosophy, menus and history can be found on their website.