We know that we can customize http headers for php curl using CURLOPT_HTTPHEADER. But if we do not add additional headers, what http headers does curl send by default? In fact, the default http request is very simple: 3 lines with 2 headers:
GET / HTTP/1.1 Host: myprogrammingnotes.com Accept: */*
No extra http headers.
Note that this is not the minimum set of required(necessary) http headers since “Accept: */*” is not necessary as per http specification.