Variable FeedTimelineCaughtUpEntrySchema`Const`

FeedTimelineCaughtUpEntrySchema: Struct<
    {
        key: String;
        position: Number;
        subtitle: String;
        title: String;
        type: Literal<"caught-up">;
    },
> = ...

The "You're all caught up" line the feed ends on: its own id as its key and the two lines the person reads.