Definitely a fake. For six months there has been malware distribution campaign displaying a bright orange page with an unauthorized copy of the Firefox logo. It suddenly appears in a tab, and a download dialog pops up referring to a .js file. It's fake and dangerous and they set up new sites every day and somehow divert users to them through ads on websites. ''To report it:'' [[I found a fake Firefox update]] ''To minimize ads on websites:'' You can try an ad blocking extension such as https://addons.mozilla.org/firefox/addon/ublock-origin/ ''If you opened the download:'' Try all the cleaners in this article: [[Troubleshoot Firefox issues caused by malware]] (it also lists specialized forums for assistance with advanced tools)