Source

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

protected function check_edit_permission( $comment ) {
		if ( 0 === (int) get_current_user_id() ) {
			return false;
		}

		if ( current_user_can( 'moderate_comments' ) ) {
			return true;
		}

		return current_user_can( 'edit_comment', $comment->comment_ID );
	}