What tools or techniques can be used to analyze HTTP request and response data in PHP for debugging purposes?

To analyze HTTP request and response data in PHP for debugging purposes, you can use tools like `var_dump()`, `print_r()`, or `echo` statements to output the data to the browser or log files. Additionally, you can use browser developer tools like Chrome DevTools or Firefox Developer Tools to inspect the network requests and responses.

// Output HTTP request data
var_dump($_REQUEST);

// Output HTTP response data
echo "Response data: " . $response;