gnome - How to edit the notification configuration?

The notification blip that usually comes on top-right and becomes slightly transparent on hover gets its colour from the background wallpaper, but can I edit it with more options? if yes, then how?

You are looking for NotifyOSDConfiguration. Try

sudo add-apt-repository ppa:nilarimogard/webupd8
sudo apt-get update
sudo apt-get install notifyosdconfig

then either search from the dash for "notify" or run in terminal

NotifyOSDConfiguration

Capitals matter.