The PE Buy/Sell Zone on the stock overview page shows you whether a stock is trading in the Buy or Sell Zone based on its historical price-to-earnings ratio (PE ratio). The PE ratio compares a company's stock price to its earnings per share, determining whether the stock is overvalued or undervalued. Additionally, this section displays the percentage of time the stock has traded below its current PE level.

For example, Microsoft Corporation is in the Sell Zone in the screenshot below as its P/E when checked, was historically lower than the current P/E value. 

You can also get a detailed analysis by clicking on the arrow in the top-right corner of the feature. This will redirect you to a page where you can check whether the stock typically trades above or below its current PE level on a standalone or consolidated basis, during specific time frames.

For more details, visit this FAQ section.