FF you first start by looking at their long guide for version control/build instructions http://mozilla-version-control-tools.readthedocs.io/en/latest/hgmozilla

FF you first start by looking at their long guide for version control/build instructions http://mozilla-version-control-tools.readthedocs.io/en/latest/hgmozilla/index.html http://mozilla-version-control-tools.readthedocs.io/en/lates... Then you make a custom mozconfig file to disable or enable features, or to add your own extensions (ie: windows): https://developer.mozilla.org/en-US/docs/Mozilla/Developer_guide/Build_Instructions/Configuring_Build_Options https://developer.mozilla.org/en-US/docs/Mozilla/Developer_g... ac_add_options --disable-activex ac_add_options --disable-activex-scripting ac_add_options --disable-installer ac_add_options --disable-crashreporter You can further abstract this with a mozconfig wrapper https://github.com/ahal/mozconfigwrapper https://github.com/ahal/mozconfigwrapper But I agree, I can't find any documentation what exactly every feature is and why you would not want to disable/enable them. The Chromium build process is much more straight forward, or you could just use 3rd party sandbox and regular release FF.