This is the manpage formatting for https://github.com/cilium/iproute2/blob/f8636e5d0e7658288851e8bb87b47af3c97bfd81/man/man8/tc-tunnel_key.8#L100-L102 as produced by the following command:
man <(curl -L https://raw.githubusercontent.com/cilium/iproute2/f8636e5d0e7658288851e8bb87b47af3c97bfd81/man/man8/tc-tunnel_key.8 -o -)
Tunnel metadata manipulation action in tc(8) Linux Tunnel metadata manipulation action in tc(8)
NAME
tunnel_key - Tunnel metadata manipulation