Quote Originally Posted by Darth Paul View Post
And if it wasn't addressed in 3.5 core or a splatbook, it officially never existed in the first place, according to the spooky wizards.
On the contrary: the 3.5 DMG says outright that 3.5 is compatible with the "existing products", and that "these products can be used with the revision with only minor adjustments".

Of course, what constitutes "minor adjustments" can vary quite wildly.