For this to work with Firefox exported csv you need to download a script from GitHub(!) which will also read all of your passwords? Really not an acceptable workaround.
As the Firefox browser no longer provides any password export addons (since version 57), you will need to use third-party tools. There are several options to choose from, check them here: https://support.nordpass.com/hc/en-us/articles/360002451778-How-to-export-passwords-from-Firefox-.
