[bayindirh]

It might be falling back to hosts for them or if they're ending with .local or .home, it's hitting hosts file first for them.

[zaarn]

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.

[faeyanpiraat]

You can locally host .com aswell

[bayindirh]

Yes, but I'm talking about this: https://serverfault.com/a/937808