Salesforce Page Optimizer (Developer Preview) is a Chrome extension developed by Salesforce. It is designed to analyze, debug, and improve the performance of your Lightning-based community or applications.

With Salesforce Page Optimizer, you can identify performance optimization opportunities in your Lightning apps. The extension provides valuable information that can help you refine your design and enhance the overall performance for your members.

For more information on the data gathered and used by this extension, you can refer to the Settings > Privacy page.

Please note that Salesforce Page Optimizer is currently in the Developer Preview stage, indicating that it may still be undergoing testing and improvements before its full release.