[m-rev.] for post-commit review: unused interface imports

[Zoltan Somogyi]

On Tue, 10 Aug 2021 12:18:03 +1000, Peter Wang <novalazy at gmail.com> wrote:
> Consider adding the explanation from the log message
> regarding why these return "builtin" as a comment.

Done, together with the typo fix.

> The rest looks fine.

Thanks.

Zoltan.