···1818 $type: "fyi.frontpage.feed.post";
1919 /** The title of the post. */
2020 title: string;
2121- subject?: $Typed<UrlSubject> | { $type: string };
2121+ subject: $Typed<UrlSubject> | { $type: string };
2222 /** Client-declared timestamp when this post was originally created. */
2323 createdAt: string;
2424 [k: string]: unknown;