Quoting '''the-edmeister''' from https://support.mozilla.org/en-US/questions/1025706 ----------------------- 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 [https://addons.mozilla.org/en-US/firefox/addon/stylish/ Stylish] and this UserStyle. https://userstyles.org/styles/104673/about-home-hide-snippets-and-hide-brand-logo

Or you can just change your homepage in Options > General.