Man pages matching name tcpserver in section 1:

tcpserver.1.en	debian 10 / ucspi-tcp
tcpserver.1.en	debian 10 / ucspi-tcp-ipv6
tcpserver.1.en	debian 11 / ucspi-tcp
tcpserver.1.en	debian 11 / ucspi-tcp-ipv6
tcpserver.1.en	debian 12 / ucspi-tcp
tcpserver.1.en	debian 12 / ucspi-tcp-ipv6