Assign domain to local network device

I've got a router cascade with OpenWrt running as the router for my local network, and it's set up behind the ISP's router. I also set up unbound as DNS server parallel to dnsmasq, as per the instructions on Github: HOW TO: Integrate with DHCP - Parallel dnsmasq.

I'd like to run a server with YunoHost in my local network (not accessible from outside). Since YunoHost needs a domain, I used yunohost.local based on their installation guide. I can reach the server via its IP address, but not under the domain. The instructions mention mDNS and describe a configuration with screenshots from a french router (see Local network access to your server). I'm not quite sure where in OpenWrt I need to make the necessary settings. In LuCi I've found:

  1. Network/DHCP and DNS/Hostnames

Hostnames are used to bind a domain name to an IP address. This setting is redundant for hostnames already configured with static leases, but it can be useful to rebind an FQDN.

  1. Network/DHCP and DNS/General option Addresses

Resolve specified FQDNs to an IP.
Syntax: /fqdn[/fqdn…]/[ipaddr].
/example.com/ returns NXDOMAIN.
/#/ matches any domain (and returns NXDOMAIN).
/example.com/# returns NULL addresses (0.0.0.0, ::) for example.com and its subdomains.

I tried both, but didn't get it working. It works via an entry in the hosts file of the client, but I'd like to use DHCP for this, especially since the hosts file isn't accessible on all devices.

Does anyone happen to know which setting is the right one here?

The solution was simpler than expected. The problem was the TLD in the given host name yunohost.local. After changing it to .lan, it works.

.local is actually a standard. Does anyone know a reason why OpenWrt does not use or respect this?

Possibly related Use .home.arpa as default TLD for local network.

Yes, .local is a standard, for mDNS/ zeroconf/ Bonjour/ AVAHI.
…but NOT for DNS, it mustn't be used as such - and therefore is invalid as a (DNS resolved) domain name/ hostname.

mDNS != DNS.