function traverse(node) {
      for (const error of node.explanations) {
        const bfCacheErrorsMap = notRestoredReasonsTree[error.type];
        const frameUrls = bfCacheErrorsMap[error.reason] || [];
        frameUrls.push(node.url);
        bfCacheErrorsMap[error.reason] = frameUrls;
      }

      for (const child of node.children) {
        traverse(child);
      }
    }
@param {LH.Crdp.Page.BackForwardCacheNotRestoredExplanationTree} node