During the install of Firefox, the browser does show import wizard to bring data –such as bookmarks, passwords and history — from other browsers into Firefox, Mozilla is planning to not show importer at all on a computer that doesn’t have their browser installed before, instead the company wants the important data migration from other browsers to complete automatically and silently (this applies for a clean and non-reset profile) on first startup of browser and offer the user the undo functionality for imported data.
When Mozilla implements this, Firefox shows a notification to the user on new tab page like this after data migration has been complete: ‘We’ve got your back. Firefox has already imported your data from other browsers you’ve used in the past. Don’t want your browser data imported? You can quickly undo the import’. Target milestone for this change has been set to Firefox 50.