Source

File: wp-includes/rest-api/endpoints/class-wp-rest-terms-controller.php

protected function get_term( $id ) {
		$error = new WP_Error(
			'rest_term_invalid',
			__( 'Term does not exist.' ),
			array( 'status' => 404 )
		);

		if ( ! $this->check_is_taxonomy_allowed( $this->taxonomy ) ) {
			return $error;
		}

		if ( (int) $id <= 0 ) {
			return $error;
		}

		$term = get_term( (int) $id, $this->taxonomy );
		if ( empty( $term ) || $term->taxonomy !== $this->taxonomy ) {
			return $error;
		}

		return $term;
	}