WebDriver for Firefox
Proxy for using W3C WebDriver compatible clients to interact with Gecko-based browsers.
This program provides the HTTP API described by the WebDriver protocol to communicate with Gecko browsers, such as Firefox. It translates calls into the Marionette remote protocol by acting as a proxy between the local- and remote ends.
Selenium (work in progress)
geckodriver is made available under the Mozilla Public License.
Its source code can be found in mozilla-central under testing/geckodriver. This GitHub repository is only used for issue tracking and making releases.
The mailing list for geckodriver discussion is https://groups.google.com/a/mozilla.org/g/dev-webdriver.