Firefox browser disables the backspace key to prevent users from accidentally losing data typed on forms.
In 2014, Google removed the ability to return to a previous page using the backspace key, as it could cause the loss of data entered on forms on the current page.
Respectively, seven years ago, the company Mozilla opened an error post to discuss whether the backspace key should be disabled, but finally decided then not to make changes.
Six years later, Mozilla finally decided to implement this change, since Firefox and Internet Explorer 11 are the only browsers that support this keyboard shortcut !.
We read from her notes Firefox Nightly version 86.0a1: To avoid losing user data when filling out forms, the Backspace key as a navigation shortcut for "Go back one page" has been turned off. You can re-enable the Backspace keyboard shortcut if you go to the page about: config and set it browser.backspace_action to 0. You can also use the recommended shortcut Alt + left arrow ”.
The change is now available in the latest nightly version of Firefox for users to try.