When I write email and say that I am attaching a document, I frequently send the mail and forget to attach the document. We’re all working too fast and off it goes. So I thought I’d write an extension for Thunderbird to check for the string attach. Just as I was about to do this, I decided to check if there was such an extension already. And sure enough there was – attachment reminder by Philipp Kewisch and Daniel Folkinshteyn. And sure enough it works nicely with my version of Thunderbird.