Something appeared in xp compiled source code but not in instead xp

[wyf180]

I checked xp compiled source code and found qbasic in nt 4.0 and test styles in whistler whitch not exit in final installed xp still in it.Does anyone know any else pervious files in xp complied files but not in final xp?Because I don't have enough time to check too many files ,I need cyber friends here to help me.