This is a container with dnsmasq installed on Alpine Linux.
The default /etc/dnsmasq.conf file is configured as a resolver with DNSSEC and log-queries enabled.
The file reference-dnsmasq.conf in /etc is a copy of the config file from the installation. It isn't loaded and is there only for reference.
Dnsmasq version 2.84rc2 Copyright (c) 2000-2021 Simon Kelley
Compile time options: IPv6 GNU-getopt no-DBus no-UBus no-i18n no-IDN DHCP DHCPv6 no-Lua TFTP no-conntrack ipset auth cryptohash DNSSEC loop-detect inotify dumpfile