wp-includes/rest-api/fields/class-wp-rest-meta-fields.php:56Registers the meta field.
public function register_field() { _deprecated_function( __METHOD__, '5.6.0' ); register_rest_field( $this->get_rest_field_type(), 'meta', array( 'get_callback' => array( $this, 'get_value' ), 'update_callback' => array( $this, 'update_value' ), 'schema' => $this->get_field_schema(), ) ); }Introduced in 4.7.0. Unchanged from 6.7.7 through 7.1.0.
Signature, return type and hooks compared across 5 parsed releases.
src/wp-includes/rest-api/fields/class-wp-rest-meta-fields.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.