As talked about back in November, 21 years after the bug report / feature request was raised, Firefox is finally supporting the XDG Base Directory Specification . This common Linux desktop specification lays out where application data files, configuration files, cached assets, and other files and file formats should be positioned within a user's home directory and the XDG environment variables for accessing those locations. Up to now, Firefox on Linux has just always tossed its user files within ~/.mozilla .
Firefox 147 also delivers on WebGPU support to all macOS configurations, zero-copy video hardware decoding is now enabled for AMD GPUs, support for the Safe Browsing v5 protocol, automatic Picture-in-Picture player window if a playing video is ever backgrounded, and support for IETF RFC 9842 Compression Dictionaries. More details on the developer additions with Firefox 147 via developer.mozilla.org .
Those relying on the upstream Mozilla binaries of Firefox can grab the freshly-built Firefox 147.0 release at Mozilla.org .