I went to get an API key for my StackOverflow C++ wrapper, and discovered that this involves registering an "application".
Does the wrapper count as an app?
A library should take an app key, not have an app key. Don't register it.
Also, make absolutely sure your wrapper demands an app key at initialization. You don't want a user locked into the No Key
request limit erroneously.
If libraries had keys an application abusively using your library (through no fault of yours) could get every application that uses your library blocked.