wp-includes/rest-api/class-wp-rest-request.php:653Sets body content.
$datastring public function set_body( $data ) { $this->body = $data; // Enable lazy parsing. $this->parsed_json = false; $this->parsed_body = false; $this->params['JSON'] = null; }Introduced in 4.4.0. Unchanged from 6.7.7 through 7.1.0.
Signature, return type and hooks compared across 5 parsed releases.
src/wp-includes/rest-api/class-wp-rest-request.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.