Doc for package: isc-dhcp-relay-ipv4?

For package: isc-dhcp-relay-ipv4 i search the documentation not found on wiki

This package is fine because i can use IPTV with Netgear SRX5308 4 * Wan router and my Orange LiveBox 5 .

Wan OpenWrt port is connected between Lan Livebox 5 & Lan SRX5308

Did you look at the software developer's site?