Your Airbrake API key is exposed on the client side. I would fix that up as soon as possible.
It is my understanding that running airbrake in the browser does need you to somehow provide the API key to the client[1].
Could you explain a bit more in detail what makes you worry about having the API key on the client?
[1]http://help.airbrake.io/kb/troubleshooting-2/javascript-noti...