You can find it on Firefish's GitLab snippets (which I may or may not have inaugurated, we'll see if it stays there in the future :blobcateyes:)
The plugin was recently updated to v0.2, which fixed a bug on the
timeToKeep and adds a confirmation when installing the plugin, to make sure that nobody ends up with deleted notes by mistake.The base of the code was inspired by @box464's great Plugins doc, thanks a bunch for that.