Enter the keys of the Efficy projects (K_PROJECT), separated by semicolons (;), you use for additional, custom needs.
Open the project in Efficy (in the editing mode) to find its key on the browser’s address bar.
Mind you, this is just one step in the configuration of the Efficy service Watch Doc!
detailed instructions: services and processes > service Watch Doc > configuring the database storage
more info on the Watch Doc service: services and processes > service Watch Doc