Firefox is set to block hidden user authentication methods by default

В night assembly Firefox, which will form the basis of the January 7 release of Firefox 72, by default is included protection against user tracking using methods of hidden identification (“browser fingerprinting”). Stealth Tracking Protection is enabled in the default default inappropriate content blocking mode and is enforced by additional categories in the Disconnect.me list, which includes hosts found to be using scripts for hidden identification.

Hidden identification refers to the storage of identifiers in areas not intended for permanent storage of information ("Supercookies"), as well as the generation of identifiers based on indirect data, such as screen resolution, list of supported MIME types, header-specific options (HTTP / 2 и HTTPS), analysis of established plugins and fonts, availability of certain Web APIs specific to video cards features rendering with WebGL and Canvas, manipulation with CSS, analysis of the features of working with mouse и keyboard.

Source: opennet.ru