So why write this article? Because . As a crypto holder, you need to know how attackers think. As a sysadmin, you need to audit your backups. As a white-hat, you might find exposed wallets and have a legal duty to report (not steal).
The intitle:index.of command is a Google dork (a search string using advanced operators). It reveals directory listings on web servers. When a webmaster forgets to disable directory indexing, Google indexes the file structure like a library catalog. You see raw folders, subfolders, and files—including backups.