[TYPO3-english] question about TypoScript code

[tom]

Hi,
...
temp.menu_1.1 {
    # Normal state properties
  NO.allWrap = <div class="menu1-level1-no"> | </div>
    # Enable active state and set properties:
  ACT = 1
  ACT.allWrap = <div class="menu1-level1-act"> | </div>
}
...

Above code is from MTB1, my question is where can I look up the
definition(usage) of NO.allWrap, ACT.allWrap? I checked TypoScript
Reference, but did not find it.

Thanks.

Tom