How does this PHP script interact with OpenAI API?

$prompt=”…text…”;
$url = 'https://api.openai.com/v1/chat/completions';
$data = [
                    "model" => "gpt-4o-search-preview",
                    "web_search_options" => [
                          "search_context_size" => "low"
                    ],
                    "messages" => [
                                  ["role" => "user",
                                  "content" => $prompt
                    ]
                    ],
                    "functions" => [
                                  [
                                  "name" => "web_search_preview",
                                  "parameters" => []
                                  ]
                    ]
                 ];
                 $jsonData = json_encode($data);
                 #
                 $headers = [
                      "Authorization: Bearer " . $apiKey,
                      "Content-Type: application/json",
                      "Content-Length: " . strlen($jsonData)
                 ];
                 #
                 $options = [
                        "http" => [
                         "method"  => "POST",
                         "header"  => implode("\r\n", $headers),
                         "content" => $jsonData
                       ]
                 ];
                #
                $context  = stream_context_create($options);
                $result =  @file_get_contents($url_, false, $context);
                if ($result === FALSE) {  
                    … 

                }else{
                   $response = json_decode($result, true);
                   $responseData = $response['choices'][0]['message']['content'];                      
                   …..
                }