For compatibility with the file-based Spotlight, DEVONthink writes thousands of proxy files into a cache folder. As long as you don’t rebuilt this cache, you can use these proxy files for linking to documents inside your DEVONthink database from other applications, for example OmniFocus. First do a Spotlight search for the document that you want to link to, then drag this file to your OmniFocus task or create a link to it in whatever application you’re using. Thank you, Peter, for this tip.
Attention: This use was not intended by us and rewriting the Spotlight cache can break the link at any time.