EFL Edje Theme Editor (Eflete) is a EFL theme editor with some convenient functions. Eflete oriented towards theme editor and UI design, and not GUI over the edc syntax.
To apply created theme to elementary you should place exported .edj-file to elementary themes dir (default: /usr/local/share/elementary/themes). Note do not forget to add read permissions to copied file. After that theme will be available for selection from elementary_config.