Some fields in CEconItem are present in actual Steam inventory responses but are missing in the documentation and also not typed in the DefinitelyTyped steamcommunity/classes/CEconItem
Fields (Not Documented or Typed)
icon_url // (Yes, I’m aware of .getImageURL(), but the raw field still exists.)
owner_descriptions
actions
const icon = (item as any).icon_url;
const ownerDescriptions = (item as any).owner_descriptions;
I'd be happy to contribute but I'm pretty tired right now as it is past 1am. Might get around to it at some point, might not.
Much love