Unlocked games in a humble bundle

So how do you redeem them

Sounds like a gift copy for the bundle. If I remember correctly, if you redeem the gift using your own e-mail it should then send you the actual bundle URL which will remain unclaimed. At that point it's as if you got it as a non-gift bundle (except you can't increase the payment amount if still within 30 days of the bundle ending). You can then view the unclaimed page and see what's in the bundle. The reason they do it that way with gift bundles is so that the person you gift it to can't see what you paid for it.

There's no way to check a gift url.
Your best option would be to check your payments (amount and date) and then take an educated guess which bundle type it could be ;)

Edit: or gift the unredeemed bundle to yourself and check the key page, if that's an option.