The "site:" operator is a Google search operator that allows you to search for results within a specific website. For example, if you wanted to search for information about cats on the website Pets.com, you could use the search query "site:pets.com cats". This would return all results on the Pets.com website that are related to cats.

Recruiters use it in x-raying platforms like LinkedIn to find candidates.

You can also use the "site:" operator to find out what pages on a website are indexed by Google. For example, if you enter the search query "site:pets.com" into Google, it will return a list of all the pages on the Pets.com website that are currently indexed by Google. This can be useful if you're trying to troubleshoot why a certain page on your website is not showing up in Google search results.

Keep in mind that the "site:" operator only works for websites that are actually indexed by Google. If a website is not indexed by Google, then using the "site:" operator will not return any results.