This an leftover from early development, it was an ability that was basically 'buyable time-limited maphack'. It was found on an neutral building(Thieves Guild) that asked the ability user whom to spy on in an dialog box and then deducted the gold cost per unit and buildings the chosen target player has, for an duration all of target player's buildings and units would reveal themselves.
On their own they dont do anything and are probably disabled alltogether.