WordPress at a glance
function is not described

Requests_Session::patch() public WP 1.0

Send a PATCH request

Note: Unlike {@see post} and {@see put}, $headers is required, as the specification recommends that should send an ETag

{} It's a method of the class: Requests_Session{}

No Hooks.

Return

Null. Nothing.

Usage

$Requests_Session = new Requests_Session();
$Requests_Session->patch( $url, $headers, $data, $options );

Code of Requests_Session::patch() WP 5.5.1

<?php
public function patch($url, $headers, $data = array(), $options = array()) {
	return $this->request($url, $headers, $data, Requests::PATCH, $options);
}