This application was developed to be used without a facebook account. Therefore it does not use the facebook API. Instead it opens the facebook event URI and downloads the website source code. This source contains the information which is used to create a calendar entry.
The source code for this application is available at GitHub.
If you encounter an issue, please report it to me anonymously at the Bugtracker or directly at GitHub.
I develop this application in my free time. If you like it, you can donate at PayPal.