Version:            (using Devel)
OS:                Linux
Installed from:    Compiled sources

I would like a search feature in the System Settings, under Notifications::System Notifications. Look at i.e. the current plasma widget adding dialog, where  you type in the search box, and the contents are just filtered.

This feature would also make it need a way to list "All Notifications", that way if you do not  know which module it is in, or are too lazy, just type in part of the text (description, title, etc.)