bookmark/received/get - Returns a single existing received bookmark.id - The ID of the received bookmark to get.{id: <number> - The ID of the received bookmark.sender_username: <string> - The username of who sent the bookmark.url: <string> - The URL of the received bookmark.title: <string> - The title of the received bookmark.tags: <string> - The space-separated list of tags.insert_time: <number> - The Unix timestamp of when the bookmark was received.}RECEIVED_BOOKMARK_NOT_FOUND - A received bookmark with the ID doesn't exist.