Mozilla/5.0 (X11; Linux x86_64; rv:66.0) Gecko/20100101 Firefox/66.0 ID:20190107214730

STR:
Type firefox --help in the console or man firefox

ER:
The -reset-profile option should be listed and documented

AR:
No documentation

Bug reported through our enterprise mailing list, the page https://developer.mozilla.org/en-US/docs/Mozilla/Command_Line_Options should be updated when this bug is fixed.

Note that this argument doesn't really do what one may think… it only creates a blank profile (and makes it the new default?), it doesn't migrate the data from the previous profile like the button in about:support does. To get that you need --migration too (plus maybe some environment variables?). That is how our installer invokes it[1]

[1] https://searchfox.org/mozilla-central/rev/7adb490485eff0783071a3e132005bceeb337461/browser/installer/windows/nsis/stub.nsi#1675,1693