A FOSS Browser is a free, open source web browser that is made available to the public for free, with no restrictions. It is typically developed and maintained by a community of independent developers, who collaborate on and contribute to the codebase. FOSS Browsers often provide users with an alternative to proprietary software and services, and are often more secure, private, and customizable than their commercial counterparts. FOSS Browsers are designed to be compatible with a wide range of web standards, including HTML, CSS, and JavaScript, and are usually built on the same underlying infrastructure as other popular browsers. They often feature additional privacy and security settings, as well as the ability to easily customize the look and feel of the browser. In addition, FOSS Browsers often provide users with access to a wider range of add-ons and extensions than their commercial counterparts.
Warning UC browser leaks private, personally identifiable information to a server in China: https://citizenlab.ca/2016/08/a-tough-nut-to-crack-look-privacy-and-security-issues-with-uc -browser/