I found this blogpost ("That's Not a Bug, It's a Feature Request") that is of course completely and entirely unrelated to the StackExchange network1:
I wish we could, as an industry, spend less time fighting tooth and nail over definitions, painstakingly placing feedback in the "bug" or "feature request" buckets -- and more time doing something constructive with our users' feedback.
However, SE metas still require users to choose between bug and feature-request. This doesn't seem to make a whole lot of sense. So please, provide some discussion or at least explanation regarding this.
More interestingly, as can be seen with this post, a bug/feature-request can be a discussion at the same time: Personally, this looks like a bug to me, and it is a feature-request at the same time but I'm okay with a discussion, explaining why the status quo makes sense (despite the aforementioned blog post).
1: I hope I don't need an irony tag for that statement ...
Edit: I'm actually mainly looking for an authoritative answer.