Virtual package ftp is provided by:
dpkg-query: no packages found matching ftp-ssl Desired=Unknown/Install/Remove/Purge/Hold | Status=Not/Inst/Conf-files/Unpacked/halF-conf/Half-inst/trig-aWait/Trig-pend ||/ Name Version Architecture +++-==========-=============-==================================== ii tnftp 20210827-4+b1 amd64 enhanced ftp client 1 packages