Typically, the country-code top level domain (ccTLD) is just that — a country code. For instance, example.co.uk has content for the UK, and example.com.au has content for Australia. Usually, registration of these domains is restricted. You have to prove that you are operating the site from the designated country. However, some countries have opened up registration to everyone. And of course, some top level domains, such as .com, are inherently generic.
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