[racket] top-level-rename

The program below produce bytecodes for the program that returns a
syntax-object representing 42.

The syntax-object looks like this:

    (#s((stx zo 0)
           #s((wrapped zo 0)
              42
              (#s((top-level-rename wrap 0 zo 0) #f)
               #s((top-level-rename wrap 0 zo 0) #f)
               #s((top-level-rename wrap 0 zo 0) #t)
               #s((phase-shift wrap 0 zo 0) 0 #f #f #f))
              clean))))

Two questions:
   1) Why three top-level-renames and not just one?
   2) What is the meaning of the boolean flag?

/Jens Axel

#lang racket
(require compiler/zo-structs compiler/zo-parse)

(define (bytecode->zo bytecode)
  (zo-parse
   (open-input-bytes
    (with-output-to-bytes
        (λ () (write bytecode))))))

(define (stx->zo x)
  (parameterize ([current-namespace (make-base-empty-namespace)])
    (namespace-require 'racket/base)
    (bytecode->zo (compile x))))

(stx->zo '(syntax 42))