Usando o comando run: ( WIN + R ) digite "% TEMP%" e pressione enter.
Isso trará todos os arquivos temporários armazenados em seu PC através da conta de usuário em que você está.
O 7-zip informa a localização temporária que ele usa (extrair de 7-zip.org/faq.html):
7-Zip doesn't know folder path of drop target. Only Windows Explorer knows exact drop target. And Windows Explorer needs files (drag source) as decompressed files on disk. So 7-Zip extracts files from archive to temp folder and then 7-Zip notifies Windows Explorer about paths of these temp files. Then Windows Explorer copies these files to drop target folder.
To avoid temp file usage, you can use Extract command of 7-Zip or drag-and-drop from 7-Zip to 7-Zip.