That '''Click Me''' game is part of the Humble Mozilla Bundle promotion on the default Home Page [about:home], that loads from the Mozilla servers in the "Brand Logo" (DIV) section of about:home. ''A feature that was first used in Firefox 29 [IIRC] just prior to the start of the Olympic Games.'' Also, part of that promotion is addressed in the "Snippet" below the Search Container on the about:home page. --------------- If you want to block the "Brand Logo" section (and the "snippet" below the Search container) from ever being seen again, you can install Stylish and this UserStyle. https://userstyles.org/styles/104673/about-home-hide-snippets-and-hide-brand-logo Or just set a different homepage. See - [[How to set the home page]]