Everything the conversation actually contained
WhatsApp's own database holds far more than text. Chat Hoarding app renders all of it: voice notes, photos, videos, GIFs, audio files, documents, stickers, shared locations, contact cards, call logs (audio, video, missed), deletion markers with sender attribution (the original text is gone — but the fact someone deleted it, and who, stays in your archive), and the system events that record group changes. New message kinds get rendered as WhatsApp introduces them.