Catalin Cimpanu, writing for BleepingComputer: Mozilla will soon block the loading of data URIs in the Firefox navigation bar as part of a crackdown on phishing sites that abuse this protocol. The data: URI scheme (RFC 2397) was deployed in 1998 when developers were looking for ways to embed files in other files. What they came up with was the data: URI scheme that allows a developer to load a file represented as an ASCII-encoded octet stream inside another document. Since then, the URI scheme has become very popular with website developers as it allows them to embed text-based (CSS or JS) files or image (PNG, JPEG) files inside HTML documents instead of loading each resource via a separate HTTP request. This practice became hugely popular because search engines started ranking websites based on their page loading speed and the more HTTP requests a website made, the slower it loaded, and the more it affected a site's SERP position.