DNS over HTTPS is disabled by default in the Firefox port of OpenBSD

Firefox port maintainers for OpenBSD did not support decision on enable by default DNS over HTTPS in new versions of Firefox. After a short discussion it was decided to leave the original behavior unchanged. To do this, the network.trr.mode setting is set to '5', which causes DoH to be unconditionally disabled.

The following arguments are given in favor of such a decision:

• Applications should adhere to system-wide DNS settings, not override them;
• Encrypting DNS might not be a bad idea, but sending defaulting all DNS traffic to Cloudflare is definitely a bad idea.

DoH settings can still be overridden in about:config if desired. For example, you can set up your own DoH server, specify its address in the settings (option "network.trr.uri") and switch "network.trr.mode" to '3', after which all DNS requests will be served by your server using the protocol DoH. To deploy your own DoH server, you can use, for example, doh-proxy from facebook, DNSCrypt Proxy or rust doh.

Source: opennet.ru