Mozmill CI is a tool for running automated UI tests on Firefox builds continuously. It provides benefits like centralized reporting and the ability to test multiple locales and platforms. Currently it runs tests on candidate releases and daily builds of Firefox for English, but the goals are to test more builds, locales, and integrate with other tools to free up human resources for testing. The roadmap includes improving hardware utilization, testing localized builds, and setting up a public dashboard to monitor localization quality.