class SyntaxTree::Translation::RuboCopAST

def s(type, children, location)

it uses the rubocop-ast specializations of the nodes.
This method is effectively the same thing as the parser gem except that 
def s(type, children, location)
  ::RuboCop::AST::Builder::NODE_MAP.fetch(type, ::RuboCop::AST::Node).new(
    type,
    children,
    location: location
  )
end