The text reads "Permanent effect while in your reserve. Increase your reserve capacity by one."
So, you take up one of your two Reserve slots with Cardiff so that you gain a third Reserve slot, leaving you with...the same two you had before you played Cardiff?
What am I missing here?
If you read the explanation for Cardiff in the back of the rule book, you will see that Cardiff allows you to keep three cards in reserve not counting the Cardiff card. So it doesn't count against the three.
And since Reserve cards are played face down how do you explain the effects of any card in Reserve? Example: I have Unit in Reserve. I spend a Time Point to raise a the defence on an attack. Do I show everyone the card and then put it back in Reserve face down?
Again, the card explanations in the back mention that UNIT is played face-up in the reserve.