When rewriting documentation about dynamic DNS it was noticed that the value help strings are missing.
vyos@vyos# set service dns dynamic interface pppoe0 service Possible completions: > custom Custom or predefined service > afraid None > changeip None > cloudflare None > dnspark None > dslreports None > dyndns None > easydns None > namecheap None > noip None > sitelutions None > zoneedit None > dyndns2