A fan made a blog about the Leaderheads and Traits for Version 32.
As manual for a custom game start and documentation, i took screenshots of all the Leaderheads in Civ 4 Caveman2Cosmos which their according tooltip visible. Whenever you start a new custom game, you need to select your Leader, who has pros and cons in form of traits. Those define if e.g. a Leader is Industrious, Aggressive, Protective or Megalomanic, and also you can review from which culture a Nation derives from. This Manual is for the current Caveman2Cosmos Version 32.
To view The Leaderheads and their Traits, please visit the link below.