The specific phrase is an example of an advanced search query, commonly referred to in cybersecurity as a "Google Dork."
When malicious actors or penetration testers use a query like this, they are hunting for specific architectural vulnerabilities:
To understand what this query is looking for, we must analyze each search operator and keyword individually. Google Dorks rely on specific commands that instruct the search engine to look only at certain parts of a webpage's metadata or URL structure.
The additional guestbook and phprar components likely reflect an attempt to combine camera discovery with injection or file upload vulnerability probing against guestbook scripts. While the syntax is no longer functional in modern search engines, the underlying security lessons remain highly relevant: continue to be leading causes of preventable data exposure.