Straight forward addition to the Emacs UI. The 'd' keybinding is implemented very similar to the 'a' keybinding - it only adds a +deleted tag as well. This tag is used by notmuchsync to delete (-p "prune") files in the mailstore. I'm sending this mostly as an RFC - I use this and like it, but people seem to have strong feelings as to how they want to deal with deleting email (or for some people, how they don't want to do that at all). /D