I’m in Appearance → Logo, it’s in the texts that appear in that admin screen.
Would be worth replacing the string name by “human language”?
I can see it when I go through Site Settings → Branding, and it has been “set” by something I uploaded in the Appearance → Logo screen, although that screen does not list it as such.
For me this is typically the kind of “little thing” that makes the admin interface confusing for the first-time Discourse user, by the way.