New Android versions introduced finer settings for notifications. But they thought it was a good idea to exempt some Notification Channels from that customization, like the "Developer Options enabled"-Notification. Yeah, I know that. I did that. Now, please remove that notification.
This module enables customization for all Notification Channels again: vibrations, ringtones, importance etc.
When removing the module, the changed notification settings will stay as they were, only you won't be able to edit them anymore (until you install the module again).