Firefox --help

firefox-help.txt

Usage: c:\Users\mconley\mozilla\mozilla-central\obj-debug\dist\bin\firefox.exe [ options ... ] [URL]
       where options include:

  -h or --help       Print this message.
  -v or --version    Print Firefox version.
  -P <profile>       Start with <profile>.
  --profile <path>   Start with profile at <path>.
  --migration        Start with migration wizard.
  --ProfileManager   Start with ProfileManager.
  --no-remote        Do not accept or send remote commands; implies
                     --new-instance.
  --new-instance     Open new instance, not a new window in running instance.
  --UILocale <locale> Start with <locale> resources as UI Locale.
  --safe-mode        Disables extensions and themes for this session.
  --allow-downgrade  Allows downgrading a profile.
  -MOZ_LOG=<modules> Treated as MOZ_LOG=<modules> environment variable, overrides it.
  -MOZ_LOG_FILE=<file> Treated as MOZ_LOG_FILE=<file> environment variable, overrides it.
                     If MOZ_LOG_FILE is not specified as an argument or as an environment variable,
                     logging will be written to stdout.
  --console          Start Firefox with a debugging console.
  --headless         Run without a GUI.
  --save-recordings  Save recordings for all content processes to a directory.
  --browser          Open a browser window.
  --new-window <url> Open <url> in a new window.
  --new-tab <url>    Open <url> in a new tab.
  --private-window <url> Open <url> in a new private window.
  --preferences      Open Options dialog.
  --screenshot [<path>] Save screenshot to <path> or in working directory.
  --window-size width[,height] Width and optionally height of screenshot.
  --search <term>    Search <term> with your default search engine.
  --setDefaultBrowser Set this app as the default browser.
  --jsconsole        Open the Browser Console.
  --jsdebugger       Open the Browser Toolbox.
  --wait-for-jsdebugger Spin event loop until JS debugger connects.
                     Enables debugging (some) application startup code paths.
                     Only has an effect when `--jsdebugger` is also supplied.
  --devtools         Open DevTools on initial load.
  --start-debugger-server [ws:][ <port> | <path> ] Start the debugger server on
                     a TCP port or Unix domain socket path. Defaults to TCP port
                     6000. Use WebSocket protocol if ws: prefix is specified.
  -layoutdebug [<url>] Start with Layout Debugger
  --recording <file> Record drawing for a given URL.
  --recording-output <file> Specify destination file for a drawing recording.