server/types/entities/preferences.ts

export interface APIPreferences {
    "posting:default:visibility": "public" | "unlisted" | "private" | "direct";
    "posting:default:sensitive": boolean;
    "posting:default:language": string | null;
    "reading:expand:media": "default" | "show_all" | "hide_all";
    "reading:expand:spoilers": boolean;
}