It's not, Firefox will still check your hosts file to see if it can resolve that way. DoH is used only if using a local-only resolver doesn't work to my knowled

It's not, Firefox will still check your hosts file to see if it can resolve that way. DoH is used only if using a local-only resolver doesn't work to my knowledge. Otherwise stuff like SMBIOS, Avahi/ZC or mDNS would break too.