Hey,
first of all: I was definitely the false settings. If I set notification_light_pulse back to 0, there are no more notifications on my phone.
I actually downloaded the Andoid Studio and modified an hello world example. Since I’m familiar with Java it was no too hard to get started.
I build an apk, so you can install my app and change your settings as well (Download from my dropbox) - the app needs the permission to write settings and you need to enable “unkown sources” in your security settings. Use this on your own risk, although I assure you it is just changing the notification setting.