Source

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

protected function check_read_permission( $comment, $request ) {
		if ( ! empty( $comment->comment_post_ID ) ) {
			$post = get_post( $comment->comment_post_ID );
			if ( $post ) {
				if ( $this->check_read_post_permission( $post, $request ) && 1 === (int) $comment->comment_approved ) {
					return true;
				}
			}
		}

		if ( 0 === get_current_user_id() ) {
			return false;
		}

		if ( empty( $comment->comment_post_ID ) && ! current_user_can( 'moderate_comments' ) ) {
			return false;
		}

		if ( ! empty( $comment->user_id ) && get_current_user_id() === (int) $comment->user_id ) {
			return true;
		}

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