16.18 Supported nodelist flags

     Note that the meaning of the following flags can be negated by
     placing a '!' character in front of them, eg. !HST.

     CM, MO, HST, H96, PEP, MAX, XA, XB, XC, XP, XW, XX, MNP, V29,
     V32, V33, V34, V42, V42B, V32B, CSP.

     All FrontDoor systems should have the "XA" flag in their nodelist
     entry.