Ah cool

<?php

$curl = curl_init();

curl_setopt_array($curl, [
  CURLOPT_URL => "https://api.cloudflare.com/client/v4/zones/zone_identifier/dns_records/import",
  CURLOPT_RETURNTRANSFER => true,
  CURLOPT_ENCODING => "",
  CURLOPT_MAXREDIRS => 10,
  CURLOPT_TIMEOUT => 30,
  CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
  CURLOPT_CUSTOMREQUEST => "POST",
  CURLOPT_POSTFIELDS => "-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"file\"\r\n\r\n[\"www.example.com. 300 IN  A 127.0.0.1\"]\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"proxied\"\r\n\r\n\r\n-----011000010111000001101001--\r\n\r\n",
  CURLOPT_HTTPHEADER => [
    "Content-Type: multipart/form-data; boundary=---011000010111000001101001",
    "X-Auth-Email: "
  ],
]);

$response = curl_exec($curl);
$err = curl_error($curl);

curl_close($curl);

if ($err) {
  echo "cURL Error #:" . $err;
} else {
  echo $response;
}

<?php

$curl = curl_init();

curl_setopt_array($curl, [
  CURLOPT_URL => "https://api.cloudflare.com/client/v4/zones/zone_identifier/dns_records/import",
  CURLOPT_RETURNTRANSFER => true,
  CURLOPT_ENCODING => "",
  CURLOPT_MAXREDIRS => 10,
  CURLOPT_TIMEOUT => 30,
  CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
  CURLOPT_CUSTOMREQUEST => "POST",
  CURLOPT_POSTFIELDS => "-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"file\"\r\n\r\n[\"www.example.com. 300 IN  A 127.0.0.1\"]\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"proxied\"\r\n\r\n\r\n-----011000010111000001101001--\r\n\r\n",
  CURLOPT_HTTPHEADER => [
    "Content-Type: multipart/form-data; boundary=---011000010111000001101001",
    "X-Auth-Email: "
  ],
]);

$response = curl_exec($curl);
$err = curl_error($curl);

curl_close($curl);

if ($err) {
  echo "cURL Error #:" . $err;
} else {
  echo $response;
}