It means the comment is “distinguished” (or marked as “speak as moderator”). It basically means that the user is posting officially, in their role as community moderator. On old reddit, this was marked by a green username background.
In my opinion, lemmy should also only show the [] moderator icon when the comment is distinguished, but unfortunately that’s not the case.
In the settings, you can set your “discussion languages”. Any posts and comments in languages you didn’t select here won’t be shown to you.
The information returned by whois depends on the registry. For example, most registries for European TLDs basically just show whether the domain is registered (I say “most” because I’m not sure whether it’s actually all or if there are exceptions, but I know .de is like this). In that case, there aren’t even “whois privacy” services available from registrars. For TLDs from other countries or gTLDs, this might vary.
In either case, do note what the other comment says. Whois is not the only way to identify who runs a service.
it returns a lot of information such as registrar name, abuse contact, creation date… even though i paid extra for “whois privacy.”
If you didn’t pay for whois privacy, it would most likely return your actual name, email address, phone number, and home address instead. “Whois privacy” just means your registrar inserts their information into these fields instead, and forwards any mail they might get to you.
If you’re using lemmy-ui (the default), it should be an option in the context menu after posting a comment. I don’t think it’s possible to do while you’re still writing it.