Mozilla, the organization behind Firefox, announced that built-in FTP, a protocol for transferring files from one host to another, implementation will be removed, as they already announced last year. Mozilla also stated that the implementation is currently disabled in the Firefox Nightly and Beta pre-release channels.
According to the announcement, built-in FTP implementation will be when Firefox 88 is released on April 19, 2021. When the implementation will be removed in Firefox 90, FTP is disabled in Firefox, the browser will delegate ftp:// links to external applications.
With the deprecation, browserSettings.ftpProtocolEnabled will become read-only and attempting to set this value will have no effect. Most places where an extension may pass “ftp” such as filters for proxy or webRequest should not result in an error, but the APIs will no longer handle requests of those types.
FTP is added to the list of supported protocol_handlers for browser extensions to help offset this removal. The extensions will be able to prompt users to launch a FTP application to handle certain links.