The handling of clicking on FTP links from within Firefox will soon be passed to other applications, as Mozilla will rip out Firefox's FTP implementation.
A year ago Mozilla announced its intention to shortly disable support for FTP, but it also said it would delay the move pending how the pandemic turned out.
By February, FTP was disabled in Firefox's nightly channel and it is currently also disabled in the Beta channel. For general release, FTP will be disabled in Firefox 88 released on April 19.
At this point, when Firefox encounters an FTP link, it will attempt to pass it off to an external application.
"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," Mozilla add-ons community manager Caitlin Neiman wrote in a blog post.
"To help offset this removal, ftp has been added to the list of supported protocol_handlers for browser extensions. This means that extensions will be able to prompt users to launch a FTP application to handle certain links."
Two release cycles later in late June, Firefox 90 will have the FTP implementation removed altogether. This will also impact Firefox on Android.
"FTP is an insecure protocol and there are no reasons to prefer it over HTTPS for downloading resources," Mozilla software engineer Michal Novotny said last year.
"Also, a part of the FTP code is very old, unsafe and hard to maintain and we found a lot of security bugs in it in the past."