When activating a Steam download key, do I get to see what it contains first?

I've received a complimentary Steam download key from Ubisoft as a compensation for a problem with a different game I have purchased.

Unfortunately Ubisoft did not write what the download key contains, they only mention 'unlocking additional content'.

I'd like to see what the key contains before actually consuming it. When entering the key into Steam, does Steam tell me what the key contains, or does it just immediately use the activation key without giving me another chance to cancel the process?

Solution 1:

From my own experience and a quick web search: No, it will only tell you what a key is for after activating it.