Why does this matter for "high quality" searches? Because SSI was primarily used by , university IT departments , and sophisticated intranets in the late 90s and early 2000s.
Often, these index pages are visible because the web server is configured to display a directory list when no default index file is found. is a fundamental security best practice. If you disable listing, a malicious actor who accesses your directory will see a 403 Forbidden error rather than a clickable list of .shtml files. inurl view index shtml high quality