Web developers can add
autocomplete="off" to the HTML code of online forms to suggest that browsers not remember the input. This is often done for login pages, etc. in the name of security.
But Firefox already asks whether it’s OK to save such info—and even remembers if you press Never For This Site. And since it’s my computer, I’d like it to ask me instead.
_isAutocompleteDisabled function in
components/nsLoginManager.js to return
false blindly will do the trick: